Build a 1 Watt Linear FM Booster Circuit Diagram

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Build a 1 Watt Linear FM Booster Circuit Diagram. That RF Amplifier is for boosting small fm transmitters and bugs. It use two Philips 2N4427 and its power is about 1Watt. At the output you can drive any linear with BGY133 or BLY87 and so on. Its power supply has to give 500mA current at 12 Volts. More voltage can boost the distance but the transistors will be burned much earlier than usual.! In any case do not exceed the 15Volts. The Amp offers 15 dB in the area of 80Mhz to 110 Mhz. L4, L5, and L6 are 5mm diameter air coils, 8 turns, with wire 1mm wire diameter.An easy project, with great results.

1 Watt Linear FM Booster Circuit Diagram

1 Watt Linear FM Booster Circuit Diagram

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Simple 450Mhz Common Gate Amplifier Circuit Diagram

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Simple 450Mhz Common Gate Amplifier Circuit Diagram. This 450Mhz Common Gate Amplifier Circuit Diagram is a low noise, 3-dB typical NF, amplifier with about 10-dB gain at 450-470 MHz for VHF two-way applications. 

Simple 450Mhz Common Gate Amplifier Circuit Diagram

Simple 450Mhz Common Gate Amplifier Circuit Diagram

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Build a CW Signal Processor Circuit Diagram

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How to Build a CW Signal Processor Circuit Diagram? That is a good question but i explain this way. This circuit provides interferenced rejection for the CW operator. The 567 phase-locked loop is configured to respond to tones from 500 to 1100 Hz. The Schmitt trigger reduces the weighting effect caused by the output of the PLL remaining low after removal of the audio signal. 

Ten to 15 millivolts of audio activate the circuit. For periods of loss of signal, circuit B will automatically switch back to live receiver audio after a suitable delay. (If a relay with a 5-volt coil is not available, the circuit can also be powered from +12 volts) When circuit B is used, the contacts on relay K1 replace SI.

CW Signal Processor Circuit Diagram

Build a CW Signal Processor Circuit Diagram

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Build a Low-Noise Active Antenna Circuit Diagram

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Build a Low-Noise Active Antenna Circuit Diagram. This is a Vlf/Vhf Wideband Low-Noise Active Antenna Circuit Diagram. A 30- to 50-cm whip antenna provides reception from 10 kHz to over 220 MHz. Tl, a dual-gate MOSFET, provides low noise, high-input impedance, and high gain, The circuit is powered via the coaxial cable used to connect the antenna to a receiver.

 Low-Noise Active Antenna Circuit Diagram

 Low-Noise Active Antenna Circuit Diagram

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Best 45Mhz RF Amplifier With Crystal Filter Circuit Diagram

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Best 45Mhz RF Amplifier With Crystal Filter Circuit Diagram. A 40673 dual-gate MOSFET is matched to a crystal filter at 45 MHz. The filter impedance is around 2kQ. The + 4-V source can be made variable for gain control ( about +4 to -4V.)

Best 45Mhz RF Amplifier With Crystal Filter Circuit Diagram

Best 45Mhz RF Amplifier With Crystal Filter Circuit Diagram

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Simple Switchable Vhf Active Antenna Circuit Diagram

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This is a Simple Switchable Vhf Active Antenna Circuit Diagram. This circuit is the best circuit of Vhf . How to build Simple Switchable Vhf Active Antenna Circuit Diagram ? Lets start! The AA-7 active antenna contains only two active elements: Ql (an MFE201 N-chanriel dual-gate FET) and Q2 (a 2SC2570 ripri VHF silicon transistor), which provide the basis of two independent, switchablc RF preamplifiers.

Simple Switchable Vhf Active Antenna Circuit Diagram

Switchable Vhf Active Antenna Circuit Diagram

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Simple Transistorized Am Radio Circuit Diagram

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Simple Transistorized Am Radio Circuit Diagram.  Below is a schematic of a typical transistor AM radio. This circuit uses npn transistors. The circuit is generic; therefore, no specific values are given for some components. This circuit is for reference, to serve as a starting point for experimenters. 

Simple Transistorized Am Radio Circuit Diagram


Simple Transistorized Am Radio Circuit Diagram
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Build a 4-18Mhz Converter Circuit Diagram

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Build a 4-18Mhz Converter Circuit Diagram. The unit consists of RF amplifier Q1, local oscillatorQ2, and mixer Q3. The two bands are covered without a band switch by using an i-f or 3.5 MHz. The oscillator range is 7.5 to 14.5 MHz. Incoming signals from 4 to 11 MHz are mixed with the oscillator to produce the 3.5-MHz i-f.

Signals from 11 to 18 MHz are mixed with the oscillator to also produce an i-f of 3.5 MHz. At any one oscillator frequency, the two incoming signals are 7 MHz apart. Rf amplifier input Cl/L1 comprises a high-Q, lightly loaded, tuned circuit; this is essential for good band separation.

Build a 4-18Mhz Converter Circuit Diagram

Build a 4-18Mhz Converter Circuit Diagram

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Full Rail Excursions Line driver Circuit Diagram

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Full Rail Excursions Line driver Circuit Diagram. This is a Line driver provides full rail excursions circuit diagram. The logic input is applied to opt-isolators Ul and U2 with, respectively, npn and pnp emitter follower outputs. Dc balance is adjusted by potentiometer R2. The emitter followers drive the gates of Ql and Q2, the complementary TMOS pairs. 

With a ±12 V supply, the swing at the common source output point is about 12 V peak-to-peak. By adding a ± 18-V boost circuit, as shown, the output swing can approach the rail swing. This circuit applies the output to transformer Tl, which is rectified by diode bridge D3, regulated by U3 and U4, and then applied to the collectors of Ul and U2. Diodes Dl and D2 are forward-biased when 12-V supplies are used, but they are back-biased when the 18-V boost is used.

Full Rail Excursions - Line driver Circuit Diagram


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Build a 140W amateur radio linear amplifier 2-30Mhz Circuit Diagram

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Build a 140W amateur radio linear amplifier 2-30Mhz Circuit Diagram. This inexpensive, easy to construct amplifier uses two MRF454 devices. Specified at 80 W power output with 5 W of input drive, 30 MHz, ana 12 Vdc.

140W amateur radio linear amplifier 2-30Mhz Circuit Diagram

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Low Power Atv Jr Transmitter 440Mhz Circuit Diagram

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Low Power Atv Jr Transmitter 440Mhz Circuit Diagram. This low-power video transmitter is useful for R/C applications, surveillance, or amateur radio applications. Seven transistors are used in a crystal oscillator-multiplier RF power amplifier chain, and a high-level video modulator. A 9- to 14-Vdc supply is required. Output is 0.4 to 1.2 W, depending on supply voltage.



Low Power Atv Jr Transmitter 440Mhz Circuit Diagram
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Simple Vlf Converter Circuit Diagram

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Simple Vlf Converter Circuit Diagram.This Simple Vlf Converter Circuit Diagram uses a low-pass filter instead of the usual tuned circuit so the only tuning required is with the receiver. The dual-gate MOSFET and FET used in the mixer and oscillator aren`t critical. Any crystal having a frequency compatible with the receiver tuning range may be used. 

For example, with a 3500 kHz crystal, 3500 kHz on the receiver dial corresponds to zero kHz; 3600 to 100 kHz; 3700 to 200 kHz, etc. At 3500 khz on the receiver all one can hear is the converter oscillator, and VLF signals start to come in about 20 kHz higher.

Simple Vlf Converter Circuit Diagram

Simple Vlf Converter Circuit Diagram

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Build a Beacon Transmitter Circuit Diagram

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Build a Beacon Transmitter Circuit Diagram. This Beacon Transmitter Circuit Diagram can be used for transmitter hunts, for remote key finding, or for radio telemetry in model rockets. It can be tuned to the two meter band or other VHF bands by charging Cl and Ll. 11 is four turns of #20 enameled wire airwound, 0.25 inch in diameter (use a drill bit), 0.2 inch long, centertapped. 

The antenna can be 18 inches of any type of wire. IC2 functions as an audio oscillator that is turned on and off by IC1 about once per second. The range of the transmitter is several hundred yards. 

Beacon Transmitter Circuit Diagram

Beacon Transmitter Circuit Diagram

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Full Power Mobile Phone Jammer Circuit Diagram

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Full Power Mobile Phone Jammer Circuit Diagram.To day if we are talking about expert Cell phone Jammers we are conversing about this schematic underneath. First off all you should be very very cautious how to use this apparatus. Its completely illegal and so the reason. I post this Circuit is only for educational and testing causes. This type of apparatus is being utilised by security for VIPS, particularly at their limousines to avoid blasting device initiating while the vehicle passes from the goal cell phone-bomb. Off course there are those who use it to make a antic or to make the persons crazy in the rectangle block you are. 

The power of the jammer is currently sufficient to do your thing, but certainly you can place a 30W linear power amp at the RF output and impede a much wider locality. So, Be pleasant individual with that and recall that there are people who may need desperately to obtain or make a call and one of them could be you! And if you can't oppose of functioning the jammer do it for couple of secs. Do not forget that if you connect linear amp the unit will be a current sucker after all. 

Full Power Mobile Phone Jammer Circuit Diagram

Full Power Mobile Phone Jammer Circuit Diagram

Full Power Mobile Phone Jammer Circuit Diagram

Full Power Mobile Phone Jammer Circuit Diagram

Full Power Mobile Phone Jammer Circuit Diagram


Main Components of Jammer:
The Jammer output focus around PF0030 MOSFET amplifier by Hitachi, which offers high stability of VSWR = 20 : 1 and low power control current of 400 mA. Few things about PF0030: · Unevenness and distortion at the surface of the heat sink attached module should be less than 0.05 mm. · It should not be existed any dust between module and heat sink. · MODULE should be separated from PCB less than 1.5 mm. ·

Soldering temperature and soldering time should be less than 230°C, 10 sec. (Soldering position spaced from the root point of the lead frame: 2 mm) · Recommendation of thermal joint compounds is TYPE G746. (Manufacturer: Shin-Etsu Chemical, Co., Ltd.) · To protect devices from electro-static damage, soldering iron, measuring-equipment and human body etc. should be grounded. · Torque for screw up the heatsink flange should be 4 to 6 kg · cm with M3 screw bolts. · Don’t solder the flange directly. · It should make the lead frame as straight as possible. ·

The module should be screwed up before lead soldering. · It should not be given mechanical and thermal stress to lead and flange of the module. · When the external parts (Isolator, Duplexer, etc.) of the module are changed, the electrical characteristics should be evaluated enough. · Don’t washing the module except lead pins. ·

To get good stability, ground impedance between the module GND flange and PCB GND pattern should be designed as low as possible. Next comes the MAX2622 a self-contained voltage- controlled oscillators (VCOs) combine an integrated oscillator and output buffer in a miniature 8-pin ?MAX package. The inductor and varactor elements of the tank circuits are integrated on-chip, greatly simplifying application of the part. In addition, the center frequency of oscillation and frequency span are factory preset to provide a guaranteed frequency range versus control voltage. An external tuning voltage controls the oscillation frequency. The output signals are buffered by an amplifier stage matched on-chip to 50?.

The MAX2622 VCO is implemented as an LC oscillator topology, integrating all of the tank components on-chip. This fully monolithic approach provides an extremely easy-to-use VCO, equivalent to a VCO module. The frequency is controlled by a voltage applied to the TUNE pin, which is internally connected to the varactor. The VCO core uses a differential topology to provide a stable frequency versus supply voltage and improve the immunity to load variations. In addition, there is a buffer amplifier following the oscillator core to provide added isolation from load variations and to boost the output power. Output Buffer: The oscillator signal from the core drives an output buffer amplifier.

The amplifier is constructed as a common-emitter stage with an integrated on-chip reactive output match. No external DC blocking capacitor is required, eliminating the need for any external components. The output amplifier has its own VCC and GND pins to minimize load-pulling effects. The amplifier boosts the oscillator signal to a level suitable for driving most RF mixers. Tune Input: The tuning input is typically connected to the output of the PLL loop filter. The loop filter is presumed to provide an appropriately low-impedance source.

It may incorporate an extra RC filter stage to reduce high-frequency noise and spurious signals. Any excess noise on the tuning input is directly translated into FM noise, which can degrade the phase-noise performance of the oscillator. Therefore, it is important to minimize the noise introduced on the tuning input. A simple RC filter with low corner frequency is needed during testing in order to filter the noise present on the voltage source driving the tuning line. Layout Issues:

Always use controlled impedance lines (microstrip, coplanar waveguide, etc.) for high-frequency signals. Always place decoupling capacitors as close to the VCC pins as possible; for long VCC lines, it may be necessary to add additional decoupling capacitors located further from the device. Always provide a low-inductance path to ground, and keep GND vias as close to the device as possible. Thermal reliefs on GND pads are not recommended. Circuit Description: The circuit emits a carrier that sweeps across the cellular band.

The Regulator S-80830ALY is made by SEIKO and is a 3V high precision device and you can use any other similar regulator. The 78L05 on the other hand provide with 5 volts the ~1KHz sweeper circuit (which consist from the NPN transistor 2N4401 and the LM741) and the MAX2622 who does the oscillation to the desired frequency. TR1 is the main frequency adjuster and TR3 adjust the signal for best spectrum damage and should be set to slightly less than 1 Volt peak to peak. TR2 is for tunning the output of approximately 880 MHz (~1.2V). You can use any 12V power supply and 1A should be enough. Finally TR4 adjusts the RF power output to 200-300 mW. Do not forget to ground the PF0030 MOSFET amplifier and put a nice heatsink as well.

Coaxial cable RG58 or any other type 50hom cable should be used between the pin7 of MAX2622 and pin1 of Hitachi PF0030 (RF to that point should be +13dBm MAX) and offcourse coaxial at the output to the antenna. Coils L1, L2 and L3 are Ferrite Beads. For antenna, if you want best results, you need a high gain omnidirectional antenna. Can also be used to jam 800 MHz radios as well as SMR radios and may do damage to ISM 900 MHz band. The third harmonic of a sweeping 800 - 828 MHz signal will jam devices operating in the 2.4 GHz ISM band. Anyway by careful with that little monster.


Sourced by: maxim
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Build a Variable Bandpass Audio Filter Circuit Diagram

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Build a Variable Bandpass Audio Filter Circuit Diagram. This Variable Bandpass Audio Filter Circuit Diagram is a variable audio bandpass filter that has a low cutoff variable from about 25 Hz to 700 Hz and a high cutoff variable from 2.5 kHz to over 20 kHz. Roll off is 12 dB/octave on both high and low ends. R2-a-b and R6-a-b are ganged potentiometers for setting lower and upper cutoff frequencies, respectively.


Variable Bandpass Audio Filter Circuit Diagram

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Low Pass Filter Circuit Diagram

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Simple and Fast Response Settling Low-Pass Filter. By introducing an extra transmission zero to the stopband of a low-pass filter, a sharp roll-off characteristic can be obtained. The filter design example of Fig. 30-l(a) shows that the time-domain performance of the low-pass section can also be improved. Figure 30-1 (b) shows the attenuation characteristic of the proposed circuit. Position of the transmission zero is determined by the passive components around the first op amp. 

It was chosen to obtain 60 dB of rejection at 60 Hz. A suitable fourth-order Bessel filter has the frequency response, as shown by the dashed line. Its response to a step input is characterized by settling time to 0.1 % of 1.8 -f Fc = 180 ms. Figure 30-l(c) and 30-l(d) represent the step response for the filter of Fig. 30-l(a) in both normal and expanded voltage scales. As you can see, settling time to 0.1% is below 100 ms; overshoot and ringing, stay below 0.03%. 


Low Pass Filter Circuit Diagram


This quite significant speed and accuracy improvement can be a major factor, particularly for low-frequency applications. Averaging filter for low-frequency linear or true rms ac-to-dc converters is an example. Some anti-aliasing applications can also be considered. For best results, resistance ratios R4-rR5 = 20, Re + R$=1A, and capacitance ratios C3 + C2 = C3 -f C4 = 4.7 should be kept up for any selected Fc.
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Build a Amplifier Attenuator Circuit Diagram

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Build a Amplifier Attenuator Circuit Diagram. A op amp and transistors Q1 and Q2 exponential converter to generate an exponential gain control current, which is introduced into the rectifier. A reference current of 150 pA, (15 V and RZO = lOO-k), is attenuated by a factor of two (6 dB) for each increase of tension in the control voltage. Capacitor C6 slows secure changes to a period of 20 IDS constant (C6 x IR) such that a sudden change in the control voltage will produce a gain change smooth sound. RI8 ensures that for control voltages of the circuit will go to great attenuation full. 

The rectifier bias current which would normally limit the gain reduction around 70 dB. RI6 attracts more courses of the rectifier. After about 50 dB of attenuation to -6 dB / V slope, with the increase in slope and the attenuation becomes much faster than the circuit to close completely at about 9 V control voltage. Al should be a low noise, high intensity, scanning speed, op. R13 and R14 in place around 0 V bias to the output.


Amplifier Attenuator Circuit Diagram

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Simple Timi Amplifier Using Lm1895N Circuit Diagram

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Simple Timi Amplifier Using Lm1895N Circuit Diagram. This circuit with 3-V to 9-V supplies, this amplifier can provide from 100-mW to 1-W output into a 4 and bandwidth is approximately 20 kHz @ 3 dB. This circuit is useful for low-power and battery applications. Drain is 80 mA @ 3 V or 270 mA @ 9 V at maximum signal conditions. 


Timi Amplifier Using Lm1895N Circuit Diagram

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Build a Tone Burst Generator Circuit Diagram

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Build a Tone Burst Generator Circuit Diagram. This is a simple Tone Burst Generator Circuit Diagram. The tone burst generator supplies a tone for one-half second after the power supply is activated; its intended use is a communications network alert signal. Cessation of the tone is accomplished at the SCR, which shunts the timing capacitor CI charge current when activated. 

The SCR is gated on when C2 charges up to the gate voltage which occurs in 0.5 seconds. Since only 70 ?? are available for triggering, the SCR must be sensitive enough to trigger at this level.The triggering current can be increased, of course, by reducing R2 (and increasing C2 to keep the same time constant). 




If the tone duration must be constant under widely varying supply voltage conditions, the optional Zener diode regulator circuit can be added, along with the new value for R2 R2' = 82 kfi. If the SCR is replaced by an npn transistor, the tone can be switched on and off at will at the transistor base terminal.
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Simple Stereo VU Meter

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I like to see lights move to music. This project will indicate the volume level of the audio going to your speakers by lighting up LEDS. The LEDS can be any color so mix them up and really make it look good. The input of the circuit is connected to the speaker output of your audio amplifier. You want to build two identical units to indicate both right and left channels. The input signal level is adjusted by the 10k ohm VR. If you wish to make a very large scale model of this unit and hang it on your wall there is an optional output transistor that can drive many LEDS at once. The unit I built drove three LEDS for each output. The sequence of the LEDS lighting are as follows Pin 1, 18, 17, 16, 15, 14, 13, 12, 11, 10.


Simple Stereo VU Meter


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Mains Supply Failure Alarm

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Whenever AC mains supply fails, this circuit alerts you by sounding an alarm. It also provides a backup light to help you find your way to the torch or the generator key in the dark. The circuit is powered directly by a 9V PP3/6F22 compact battery. Pressing of switch S1 provides the 9V power supply to the circuit. A red LED (LED2), in conjunction with zener diode ZD1 (6V), is used to indicate the battery power level.

Resistor R9 limits the operating current (and hence the brightness) of LED2. When the battery voltage is 9V, LED2 glows with full intensity. As the battery voltage goes below 8V, the intensity of LED2 decreases and it glows very dimly. LED2 goes off when the battery voltage goes below 7.5V. Initially, in standby state, both the LEDs are off and the buzzer does not sound. The 230V AC mains is directly fed to mains-voltage detection optocoupler IC MCT2E (IC1) via resistors R1, R2 and R3, bridge rectifier BR1 and capacitor C1.

Illumination of the LED inside optocoupler IC1 activates its internal phototransistor and clock input pin 12 of IC2 (connected to 9V via N/C contact of relay RL1) is pulled low. Note that only one monostable of dual-monostable multivibrator IC CD4538 (IC2) is used here. When mains goes off, IC2 is triggered after a short duration determined by components C1, R4 and C3. Output pin 10 of IC2 goes high to forward bias relay driver transistor T1 via resistor R7.


Mains Supply Failure Alarm Circuit Diagram

Relay RL1 energises to activate the piezo buzzer via its N/O contact for the time-out period of the monostable multivibrator (approximately 17 minutes). At the same time, the N/C contact removes the positive supply to resistor R4. The time-out period of the monostable multivibrator is determined by R5 and C2. Simultaneously, output pin 9 of IC2 goes low and pnp transistor T2 gets forward biased to light up the white LED (LED1).

Light provided by this back-up LED is sufficient to search the torch or generator key. During the mono time-out period, the circuit can be switched off by opening switch S1. The ‘on’ period of the monostable multivibrator may be changed by changing the value of resistor R5 or capacitor C2. If mains doesn’t resume when the ‘on’ period of the monostable lapses, the timer is retriggered after a short delay determined by resistor R4 and C3.
Source: EFY Mag
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Hard Disk Selector Circuit Diagram

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 Hard Disk Selector Circuit Diagram. In the last few years, the available range of operating systems for PCs has increased dramatically. Various free (!) operating systems have been added to the list, such as BeOS, OpenBSD and Linux. These systems are also available in different colours and flavours (versions and distributions). Windows is also no longer simply Windows, because there are now several different versions (Windows 95, 98, ME, NT, XP, Vista and 7). Computer users thus have a large variety of options with regard to the operating system to be used. One problem is that not all hardware works equally well under the various operating systems, and with regard to software, compatibility is far from being universal. In other words, it’s difficult to make a good choice.

 Hard Disk Selector Circuit Diagram
Switching from one operating system to another - that’s a risky business, isn’t it? Although this may be a bit of an exaggeration, the safest approach is still to install two different operating systems on the same PC, so you can always easily use the ‘old’ operating system if the new one fails to meet your needs (or suit your taste). A software solution is often used for such a ‘dual system’. A program called a ‘boot manager’ can be used to allow the user to choose, during the start-up process, which hard disk will be used for starting up the computer. Unfortunately, this does not always work flawlessly, and in most cases this boot manager is replaced by the standard boot loader of the operating system when a new operating system is installed.

In many cases, the only remedy is to reinstall the software. The solution presented here does not suffer from this problem. It is a hardware solution that causes the primary and secondary hard disk drives to ‘swap places’ when the computer is started up, if so desired. From the perspective of the computer (and the software running on the computer), it appears as though these two hard disks have actually changed places. This trick is made possible by a feature of the IDE specification called ‘CableSelect’. Every IDE hard disk can be configured to use either Master/Slave or CableSelect. In the latter case, a signal on the IDE cable tells the hard disk whether it is to act as the master or slave device. For this reason, in every IDE cable one lead is interrupted between the connectors for the two disk drives, or the relevant pin is omitted from the connector.


This causes a low level to be present on the CS pin of one of the drives and a high level to be present on the CS pin of the other one (at the far end of the cable). The circuit shown here is connected to the IDE bus of the motherboard via connector K1. Most of the signals are fed directly from K1 to the other connectors (K2 and K3). An IDE hard disk is connected to K2, and a second one is connected to K3. When the computer is switched on or reset, a pulse will appear on the RESET line of the IDE interface. This pulse clocks flip-flop IC1a, and depending on the state of switch S1, the Q output will go either high or low. The state on the Q output is naturally always the opposite of that on the Q output. If we assume that the switch is closed during start-up, a low level will be present on D input of IC1a, so the Q output will be low following the reset pulse.

 Hard Disk Selector Circuit Diagram
This low level on the Q output will cause transistor T1 to conduct. The current flowing through T1 will cause LED D1 to light up and transistor T2 to conduct. The hard disk attached to connector K2 will thus see a low level on its CS pin, which will cause it to act as the master drive and thus appear to the computer as the C: drive. A high level will appear on the Q output following the reset pulse. This will prevent T3 and T4 from conducting, with the consequence that LED D2 will be extinguished and the hard disk attached to connector K3 will see a high level on its CS pin. For this disk, this indicates that it is to act as a slave drive (D: drive).


If S1 is open when the reset pulse occurs, the above situation is of course reversed, and the hard disk attached to connector K2 will act as the D: drive, while the hard disk attached to connector K3 will act as the C: drive. Flip-flop IC1a is included here to prevent the hard disks from swapping roles during use. This could have disastrous consequences for the data on the hard disks, and it would most likely cause the computer to crash. This means that you do not have to worry about affecting the operation of the computer if you change the switch setting while the computer is running. The state of the flip-flop, and thus the configuration of the hard disks, can only be changed during a reset.

The circuit is powered from a power connector for a 3.5-inch drive. This advantage of using this connector is that it easily fits onto a standard 4-way header. However, you must observe the correct polarity when attaching the connector. The red lead must be connected to pin 1. Constructing the hard disk selector is easy if the illustrated printed circuit board is used. You will need three IDE cables to connect the circuit. The best idea is to use short cables with only two connectors, with all pins connected 1:1 (no interruption in the CS line). The IDE connector on the motherboard is connected to K1 using one cable. A cable then runs from K2 to first hard disk, and another cable runs from K3 to the second hard disk. This means that it is not possible to connect more than two hard disks to this circuit. You must also ensure that the jumpers of both disk drives are configured for CableSelect. To find out how to do this, refer to the user manual(s) for the drives.



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Build a Receiver Af Noise Limiter For Low-Level Signals Circuit Diagram

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Build a Receiver Af Noise Limiter For Low-Level Signals Circuit Diagram. A preamplifier in the audio frequency range amplifies a noisy audio signal to drive a diode clipper.Suitable audio input levels would be in the 10-mV to 1-V range. 


Build a Receiver Af Noise Limiter For Low-Level Signals Circuit Diagram

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Build a Low Distortion Amplifier cum Compressor Circuit Diagram

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Build a Low Distortion Amplifier cum Compressor Circuit Diagram. Designers can build a 15-dB compressor with a miniature lamp and a current-feedback amplifier. The circuit possesses extremely low distortion at frequencies above the lamp`s thermal time constant. This means that distortion is negligible from audio frequencies to beyond 10 MHz. There`s also relatively little change in phase versus gain compared to other automatic gain-control circuits. Lastly, the circuit has many instrumentation, audio, and high-frequency applications as a result of its low distortion and small phase change. 

The AD844 op amp is a perfect fit for this application because it`s a current-feedback amplifier. Each stage of the circuit, U2, lamp, and feedback resistor compresses an ac signal by over 15 dB (see the figure). Cascading a number of stages delivers higher compression ranges. Op amp U1 operates as a unity-gain buffer to drive the input to the compressor. However, U1 is optional if a low-impedance signal source is used. 


 Low Distortion Amplifier cum Compressor Circuit Diagram


The lamp`s resistance will increase with temperature, which reduces the ratio of resistor R3 to the resistance of the lamp. This ratio reduces the gain of U2. The lamp`s cold resistance should be greater than the input resistance of U2 (more than 50 ) for proper operation. The lamp`s resistance will change slightly for low input levels. Therefore, the ratio of R3 to the resistance of the lamp and the gain of U2 stays high.
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Simple Whooper Circuit Diagram

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This is a Simple Whooper Circuit Diagram. Integrated circuit Ul is connected as a low-frequency asymmetrical oscillator. Its output is inverted by Ql and fed to the reset terminal of U2 at pin 5. Integrated circuit U2 is configured as an audio oscillator and is enabled when the output of Ul is low. With the voltage at pin 5 of U2 constant, the circuit just` `bleeps.`` The voltage across capacitor CI is fed to the base of Q2, which turns it on and grounds pin 5 of U2. 

When the frequency of the reset signal on pin 4 falls, the output frequency of U2 rises. The output then becomes a whoop, starting low in frequency and ending high. Resistor Rl sets the repetition rate and R2 determines the time duration of the whoop. Resistors R3 and R4 set the center-operating frequency.

Whooper Circuit Diagram

Whooper Circuit Diagram

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Make a Arc Jet Power Supply Circuit Diagram

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How to make Arc-jet-power-supply-and-starting-circuit ? This Arc Jet Power Supply Circuit Diagram for starting arc jets and controlling them in steady operation is capable of high power efficiency and can be constructed in a lightweight form. The design comprises a pulse-width-modulated power converter, which is configured in a closed control loop for fast current control. 

The series averaging inductor maintains nearly constant current during rapid voltage changes, and thereby allows time for the fastresponse regulator to adjust its pulse width to accommodate load-voltage changes. The output averaging inductor doubles as the high`voltage pulse transformer for ignition. The starting circuit operates according to the same principle as that of an automobile ignition coil.

 Arc Jet Power Supply Circuit Diagram
 
Make a Arc Jet Power Supply Circuit Diagram

When the current is interrupted bY a transistor switch, the inductor magnetic field collapses, and a high-voltage pulse is produced. The pulseis initiated every 0.25 second until arc current is detected, then the pulser is automatically turned off.
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Simple Variable Dc Supply Step Circuit Diagram

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This is a Simple Variable Dc Supply Step Circuit Diagram. Intended as a replacement for generally poorly regulated `wall-type` ac/dc adapters, this Simple Variable Dc Supply Step Circuit Diagram offers superior performance to simple, unregulated adapters. 

Voltages of 3, 6, 9, and 12 V are available. The DPDT switch serves as a polarity-reversal switch. R2 through R6 can be replaced with a 2.5-kfl pot for a variable voltage of 1 to 12 V. R7 through RIO can be replaced by a fixed resistor of about 1 kfi if the LED1 brightness variation with output voltage is not a problem.


Simple Variable Dc Supply Step Circuit Diagram

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Build a Ups 5 Volt Circuit Diagram

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How to Build a Ups 5 Volt Circuit Diagram? This is a simple circuit diagram in this circuit A 9-V wall adapter supplies Vm. IC2 contains a low-battery detector circuit that senses l7IN by means of R6 and R7. The detector output Cpin 7) drives an inverter (Ql), which in turn drives the shut-down inputs Ic of 1C1 and SHDN of IC2. These inputs have opposite-polarity active levels. 

The common feedback resistors, R2 and R3 enable both regulators to sense the output voltage, V0VT. When IC2 shuts down, its output turns off. However, when IC1 shuts down, the whole chip assumes a low-power state and draws under 1 . LI, D2, Gl, C2, R2, and R3 are part of the 250-mW switching regulator. Diodes D3 and D4 wire-OR the power connection to IC2, and 03 improves the linear regulator`s load regulation.


Build a Ups 5 Volt Circuit Diagram

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Build a Hv Power Supply With 9 To 15Vdc Input Circuit Diagram

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Build a Hv Power Supply With 9 To 15Vdc Input Circuit Diagram. This Hv Power Supply is The combination Hartley oscillator/step-up transformer shown in A can generate significant negative high voltage, especially if the voltage output of the transformer is multiplied by the circuit in B. 


Hv Power Supply With 9 To 15Vdc Input Circuit Diagram

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Build a Switching Power Supply Circuit Diagram

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Build a Switching Power Supply Circuit Diagram. This is a Switching Power Supply Circuit Diagram. This low-voltage high-current output, switching de power supply is running off the 220-Vac input. In this circuit, an ST2 diac relaxation oscillator, Q3, Cl, and the diac, initiates conduction of the output switching transistor Ql, the on-time of which is maintained constant by a separate tiring computation network consisting of Q2, C2, SUS, and SCR 1

The output voltage, consequently, is dependent on the duty cycle. To compensate for unwanted variations of output voltage because of input voltage or load resistance fluctuations, an HllC wired as a linear-model unilateral PNP transistor in a stable differential amplifier configuration is connected into the galvanic ally isolated negative-feedback loop. 


Switching Power Supply Circuit Diagram

The loop determines the duty cycle and hence the output voltage. Of further interest in this circuit is the use of several low-current, high-voltage, 400V VvRM thyristors (Q2, Q3,) which are also used as pnp remote-base transistors. Short-circuit protection is assured by coupling Ql collector-current feedback into the tum-off circuitry via Rss·
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Best H-E Voltage Converter Circuit Diagram

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Best High-efficiency-fly back-voltage-converter. This is a H-E Voltage Converter Circuit Diagram.In this circuit Ul is a dual voltage comparator with open collector outputs. The A side is an oscillator operating at 100kHz, and the B side is part of the regulation circuit that compares a fraction of the output voltage to a reference generated by zener diode D2. 

The output of U1A is applied directly to the gate of Q1. During the positive half-cycle of the Q1 gate voltage, energy is stored in Ll; in the negative half, the energy is discharged into C2. A portion of the output voltage is fed back to U1B to provide regulation. The output voltage is adjustable by changing feedback potentiometer R9. 


Best H-E Voltage Converter Circuit Diagram
 

Using the component values shown will produce a nominal 300-V output from a 12-V source. However, the circuit maximum output voltage is limited by RlO; a lower value for R10 yields a higher output voltage. The output voltage is also limited by the breakdown of values Ql, L1, D1, and C2.
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Simple Mobile Voltage Regulator Circuit Diagram

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Build a Simple Mobile Voltage Regulator Circuit Diagram. This simple mobile voltage regulator circuit diagram may save your two meter or CB transceiver if the voltage regulator fails. The 2N3055 should be heat sinked if current drawn by the rig is in excess of 2 A on transmit. This simple mobile voltage regulator circuit diagram will do little under normal operating conditions, but could save expensive equipment if the vehicle`s electrical system loses regulation.



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Best Adjustable 20V Supply Circuit Diagram

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Build a Best Adjustable 20V Supply Circuit Diagram. This Best Adjustable 20V Supply Circuit Diagram, can deliver 3 A or more and a maximum dc voltage ol` a little over 20 V. It is designed around the readily available LM317T adjustable 3-terminal regulator and has a pnp power transistor to boost the current output. 

The transformer has an 18-V secondary rated at, 6 A; this feeds to bridge rectifier and two 4700- capacitors to yield around 25 Vdc. This voltage is fed to the emitter of the MJ2955 transistor and to the input of the LM317 via a 33-Ohm resistor.



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LED Volt Meter Circuit diagram

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LED Volt Meter Circuit  diagram: Here is a Simple LED Volt meter to Monitor the charge level in Lead Acid Battery or Tubular battery. The terminal voltage of the battery is indicated through a four level LED indicators. The nominal terminal voltage of a Lead Acid battery is 13.8 volts and that of a Tubular battery is 14.8 volts when fully charged. The LED voltmeter uses four Zener diodes to light the LEDs at the precise breakdown voltage of the Zener diodes. Usually the Zener diode requires 1.6 volts in excess than its prescribed value to reach the breakdown threshold level. When the battery holds 13.6 volts or more, all the Zener breakdown and all LEDs light up. When the battery is discharged below 10.6 volts, all the LEDs remain dark. So depending on the terminal voltage of the battery, LEDs light up one by one or turns off.

LED Volt Meter Circuit  diagram:

LED-Volt-Meter-circuit-diagram12 LED Volt Meter Circuit Diagram
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Simple Voltmeter Circuit Diagram

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This Simple Voltmeter Circuit Diagram provides a simple means to determine the voltage of a low-impedance voltage source. It works as follows. P1, which is a 1-W potentiometer, forms a voltage divider in combination with R1. The voltage at their junction is buffered by T1, and then passed to reference diode D1 via R3. D1 limits the voltage following the resistor to 2.5 V. An indicator stage consisting of T2, R4 and LED D2 is connected in parallel with D1. As long as the voltage is not limited by D1, the LED will not be fully illuminated. This is the basic operating principle of this measurement circuit.

Simple Voltmeter Circuit Diagram


Simple Voltmeter Circuit Diagram
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Sensitive Audio Power Meter Circuit diagram

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Sensitive Audio Power Meter  Circuit diagram: As a follow-up to the simple audio power  meter described in [1], the author has developed a more sensitive version. In practice,  you  rarely  use  more  than  1 watt  of  audio  power in a normal living-room environment.  The only time most people use more is at a  party when they want to show how loud their  stereo system is, in which case peaks of more  than 10 W are not uncommon. With this circuit, the dual LED starts to light up  green at around 0.1 watt into 8 ohms (0.2 watt  into 4 ohms). Naturally, this depends on the  specific type of LED that is used.
 
Sensitive Audio Power Meter  Circuit diagram:
Sensitive Audio Power Meter-Circuit-Diagram
Sensitive Audio Power Meter Circuit Diagram
 
Here it is  essential to use a low current type. The capacitor is first charged via D1 and then discharged via the green LED. This voltage-doubler effect  increases the sensitivity of the circuit. Above a level of 1 watt, the transistor limits the current through the green LED and the red LED con ducts enough to produce an orange hue.The red colour predominates above 5 watts. Of course, you can also use two separate ‘normal’ LEDs. However, this arrangement cannot generate an orange hue. For any testing that may be necessary, you should use  generator with a DC-coupled output. If there is a capacitor in the output path, it can cause misleading results. 
Reference: Simple Audio Power Meter, Elektor July & August 2008.

Author : Michiel Ter Burg Streampowers
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Build a 12V to 9 or 6 v Converter Circuit Diagram

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Build a 12V to 9 or 6 v Converter Circuit Diagram. This 12V to 9 or 6 v Converter Circuit Diagram enables transistorized items such as radio, cassettes, and other electrical devices to be operated from a car`s electrical supply. 

The table gives values for resistors and specified diode types for different voltage. Should more than one voltage be required a switching arrangement could be incorporated. For high currents, the transistor should be mounted on a heat-sink. 


12V to 9 or 6 v Converter Circuit Diagram

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10 KV High Voltage Power Supply Circuit Diagram

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 This is very sensitive this is a 10 KV High Voltage Power Supply Circuit Diagram. Be very careful with this power supply because uses 220V mains and has 10KV at output.

10 KV High Voltage Power Supply Circuit Diagram

10 KV High Voltage Power Supply Circuit Diagram


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Build a Simple 90Vrms Voltage Regulator Circuits Diagram

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This is a Simple 90Vrms Voltage Regulator Circuits Diagram. The 90Vrms Voltage Regulator Circuits Diagram is an open loop rms voltage regulator that will provide 500 watts of power at 90 V rms with good regulation for an input voltage range of 110-130 V rms. With the input voltage applied, capacitor Cl charges until the firing point of Q3 is reached causing it to fire. 

This turns Q5 on which allows current to flow through the load. As the input voltage increases, the voltage across R10 increases which increases the firing point of Q3. This delays the firing of Q3 because Cl now has to charge to a higher voltage before the peak-point voltage is reached.Thus the output voltage is held fairly constant by delaying the firing of Q5 as the input voltage increases. For a decrease in the input voltage, the reverse occurs.


90Vrms Voltage Regulator Circuits Diagram

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Build a Simple Single-Chip Dc Supply Circuit Diagram

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How to Build a Simple Single-Chip Dc Supply Circuit Diagram. This Simple Single-Chip Dc Supply Circuit Diagram Direct derivation of 5 to 24 Vdc from ac mains, without a transformer is possible with this circuit. Note that a direct mains connection to the dc output exists. Suitable safety precautionary must be taken.


Build a Simple Single-Chip Dc Supply Circuit Diagram

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Build a 5V 0.5A Power Supply Circuit Diagram

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The 5V 0.5A Power Supply Circuit Diagram is essentially a constant source modified by the feedback components R2 and R3 to give a constant voltage output. The output of the ZN424E need only be 2 volts above the negative rail, by placing the load in the collector of the output transistor Tr2. The current 5V 0.5A Power Supply Circuit Diagram is achieved by Trl and R5. This simple circuit has the following performance characteristics: Output noise and ripple (full load) = 1 mV rms. Load regulation (0 to 0 A) = 0%. Temperature coefficient — ± 100 ppm/°C. Current limit = 05 A.


5V 0.5A Power Supply Circuit Diagram

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Simple Switch-Mode Voltage Regulator Circuit Diagram

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This is a Simple Switch-Mode Voltage Regulator Circuit Diagram. This Simple Switch-Mode Voltage Regulator Circuit Diagram power supplies offer the benefit of a much greater efficiency than obtainable with a traditional power supply. The Simple Switch-Mode Voltage Regulator Circuit Diagram presented here has an efficiency of around 85%. An input voltage of 12 to 16 Vdc is converted into a direct voltage of exactly 5 V. 


Simple Switch-Mode Voltage Regulator Circuit Diagram



The use of a MAX638CPA enables the design and construction of the regulator to be kept fairly simple: only nine additional components are needed to complete the circuit. Resistors RI and R2 are used to indicate when the battery voltage becomes low: as soon as the voltage on pin 3 becomes lower than 1.3 V, D1 lights. With values as shown for the potential divider, this corresponds to the supply voltage getting lower than about 6.5 V. 

The output of the IC is shunted by a simple LC filter formed by LI, C3 and D2. The oscillator on board the IC generates a clock frequency of around 65 kHz and drives the output transistor via two NOR gates. The built-in error detector, the `battery low` indicator or the voltage comparator can block the clock frequency, which causes the transistor to switch off. The IC compares the output voltage of 5 V with a built-in reference (FET). Depending on the load, the FET will be switched on for longer or shorter periods. The maximum current through the FET is 375 mA, which corresponds with a maximum output current of 80 mA.
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