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Showing posts from January, 2014

Isolation and 0-V Switching logic Circuit Diagram

Isolation the process or fact of isolating These two simple circuits provide 0-V switching. They can be used with full wave bridges or in anti-parallel to provide full wave control and are normally used to trigger power thyristors. If an input signal is present during the time the ac voltage is between 0 to 7 V, the SCR will turn on. But, if the ac voltage has risen above this range and the input signal is then applied, the transistor, Ql, will be biased to the `on` state and will hold the SCR and, consequently, the relay ' 'off' until the next zero crossing. 
Isolation and 0-V Switching logic Circuit Diagram


Using a SCR Coupler


Op Amp Regulator Circuit Diagram

This is a simple Op Amp Regulator Circuit Diagram. This op amp offers a straightforward method of developing a single-polarity stable voltage source (see the figure). Transistor Ql gets a base drive through resistor Rl, and conducts to develop a voltage (Vi) across the IC`s supply pins. Amp Al, R2, and Ql form a positive-feedback closed loop, along with R3 and the zener diode. Al, R2, and Ql also form a negative-feedback closed loop with R4 and R5. 
 Op Amp Regulator Circuit Diagram


The effect of positive feedback is predominant as the non-inverting input receives Vx while the inverting input receives only: This happens until the zener comes into play. When the voltage at the inverting input exceeds the voltage at the non-inverting input, Al`s output takes away Ql`s base current through R2, which reduces Vi. Hence, an equilibrium condition is reached. Now: This circuit can source more than 30 mA.

Optical Cmos Coupler Circuit Diagram

This is a simple optical cmos coupler circuit diagram. An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras, camera modules and other imaging devices. Early analog sensors were video camera tubes; currently used types are semiconductor active pixel sensors in complementary metal–oxide–semiconductor (CMOS). Since standard CMOS logic operates down to 3-V supply voltages and is specified as low as 30 p.
 Optical Cmos Coupler Circuit Diagram


A maximum current sinking/sourcing capability, it is necessary to use a buffer transistor to provide the required current to the IRED if CMOS is to drive the optocoupler. As in the case of the low output TTL families, the H74A output can drive a multiplicity of CMOS gate inputs or a standard TTL input given the proper bias of the IRED. A onelogic stage drives the IRED on. 
This circuit will provide worst-case drive criteria to the IRED for logic supply voltages from 3 to 10 V, although…

Build a Precision Increasing Buffer Circuit Diagram

How to Build a Precision Increasing Buffer Circuit Diagram? This simple Precise Buffer Overflow Detection via Model Checking. increasing number of attacks that exploit such vulnerabilities. Precision Increasing Buffer Circuit Diagram adding an unity-gain buffer to your analog circuit can increase its precision. For example, by itself, the op amp IC1 exhibits a maximum dVosldT of 1.8 /iV7°C and can drive a 600- load. Under these conditions, IC1 would dissipate 94 mW incrementally. 
 Precision Increasing Buffer Circuit Diagram


Thus, the op amp`s 0JA of 150°C/PFr would change its vqs by 25 juY. The buffer, IC2, will isolate IC1 from the load and eliminate the change in power dissipation in IC1, thereby achieving ICl`s minimum, rated offset-voltage drive. The loop gain of IC1 essentially eliminates the offset of the buffer. Almost any unity-gain buffer will work, provided that it exhibits a 3-dB bandwidth that is at least 5 times the gain-bandwidth product of the op amp.

Simple Thermocouple Preamplifier Circuit Diagram

This is a Simple Thermocouple Preamplifier Circuit Diagram. Thermocouple, a local temp sensor and a summing amplifier you can design a practical preamplifier. As a project goal, let's design a circuit. The MAX420 is operated at a gain of 191 to convert the 52 p.VI o C output of the type J thermocouple to a 10 mV/°C signal. The -2.2 mV/°C tempco of the 2N3904 is added into the summing junction with a gain of 42.2 to provide cold-junction compensation. 
Simple Thermocouple Preamplifier Circuit Diagram
 The ICL8069 is used to remove the offset caused by the 600-m V initial voltage of the 2N3904. Adjust the 10-KO trimpot for the proper reading with the 2N3904 and isothermal connection block at a temperature near the center of the circuit` s operating range. Use the component values shown in parentheses when using a type K thermocouple.

Affordable Vhf-Uhf Diode Rf Switch Circuit Diagram

This is the very cheap low priced circuit. This is an affordable Vhf/Uhf diode Rf switch circuit diagram. This circuit uses low-cost IN4148 diodes and exhibits about 1.5 dB insertion loss from 10 to 1000 MHz with a few volts of negative bias. D3 conducts and D1/D2 are cut off, which results in 30 to 50 dB isolation. When a few volts of positive bias are applied, Dl and D2 are biased on and D3 is cut off. This circuit should be useful in applications where a low-cost RF switch is necessary.
Affordable Vhf-Uhf Diode Rf Switch Circuit Diagram


Electronic Schmitt Trigger with Programmable Hysteresis Circuit Diagram

Electronic Schmitt Trigger with Programmable Hysteresis Circuit Diagram. In electronics world, a Schmitt trigger is a comparator circuit with hysteresis, implemented by applying positive feedback to the non inverting input of a comparator.
Electronic Schmitt Trigger with Programmable Hysteresis Circuit Diagram CA 3088 is used as a versatile Schmitt trigger. The size of the hysteresis levels is determined by Ia that flows out of the amplifier`s output and through R2. Increasing Ia increases hysteresis and vice versa. The positive and negative hysteresis levels are symmetrical about 0 V.
Electronic Schmitt Trigger with Programmable Hysteresis Circuit Diagram

Build a 555 Astable Oscillator Circuit Diagram

How to build a 555 Astable Oscillator Circuit Diagram. The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation,. Astable (free-running) mode: The 555 can operate as an oscillator. This free-running multivibrator uses an external current sink to discharge the timing capacitor, C. Therefore, interval ^ may easily be 1000 the pulse duration, t1( which defines a positive output. Capacitor voltage, V^, is a negative going ramp with exponential rise during the pulse output periods. This as is has low duty cycle. 
555 Astable Oscillator Circuit Diagram


Constant Bandwidth Amplifier Circuit Diagram

This is a simple Constant bandwidth amplifier circuit diagram. For devices such as operational amplifiers that are designed to have a simple one-pole frequency will also be equal to the unity-gain bandwidth of the amplifier the bandwidth within which the amplifier gain is at least 1. The traditional restnct1on of constant gain-bandwidth products for a voltage amplifier can be overcome by employing feedback around a current amplifier
 Constant Bandwidth Amplifier Circuit Diagram

 Two current mirrors, constructed from transistors in a CA3096AE array, effectively turn the LF351 op amp into a current amplifier. Feedback is then applied by using R2 and R1, turning the whole circuit into a feedback voltage amplifier with a non-inverting gain of G of 1 + R112R2. Using the values shown, a constant bandwidth of 3.5 MHz is obtained for all voltage gains up to and beyond 100 at 10 V pk-pk output, equivalent to a gain-bandwidth product of 350 MHz from an op amp with an advertised unity gain-bandw…

Inrush Current Limiter Circuit Diagram

This is the simple inrush current limiter circuit diagram. Q1 is an npn Darling-ton and Q2 is a prip Darling-ton. MOV1 is a metal-oxide varistor and R8 is an thermistor for limiting inrush current. This circuit limits ac line current to a load. When a predetermined interval has passed, RY1 shorts out thermistor or resistance RB. R4 can be 150 kQ if R9 is not used. If power is removed, ready for immediate restart.

Inrush Current Limiter Circuit Diagram


Step up Down DC - DC Converter Circuit Diagram

Positive output step-up and step-down dc-dc converters have a common limitation in that neither can handle input voltages that are both greater than or less than the output. For example, when converting a 12-V sealed lead/acid battery to a regulated +12 V output, the battery voltage might vary from a high of 15 V down to 10 V. 
By using a MAX641 to drive separate P-and N-cbannel MOSFETs, both ends of the inductor are switched to allow noninverting buck/boost operation. A second advantage of the circuit over most boostonly designs is that the output goes to 0 V when shutdown is activated. Inefficiency is a drawback because two MOSFETs and two diodes increase the losses in the charge and discharge path of the inductor. The circuit delivers +12 V at 100 mA at 70 percent efficiency with an 8-V input.

Step up Down DC - DC Converter Circuit Diagram

Precision Full-Wave Ac-Dc Converter Circuit Diagram

A dc level is produced that corresponds to the ac input rms value (if sine wave), -i set the gain of IC2 to 1.11. This factor is the average-to-rms conversion factor. IC1 and IC2 act as a full-wave rectifier circuit, with Dl and D2. 
Precision Full-Wave Ac/Dc Converter Circuit Diagram


Simple FM transmitter Microphone Circuit Diagram

This is a Simple FM transmitter Microphone Circuit Diagram. In this circuit utlise for An op-amp IC (741) amplifies the audio signal from MIC1, and R12 controls its gain. Audio is fed to the oscillator circuit Q1 and related components. D2 is a varactor diode. Audio fed to D2 causes FM of the oscillator signal. L1 is 3 turns of #18 wire. The antenna is a 12` whip.
Simple FM transmitter Microphone Circuit Diagram

Build a Zero Crossing Switch Circuit Diagram

This is a simple Zero Crossing Switch Circuit Diagram. The zero-crossing is important for systems which send digital data over AC circuits, such as modems, X10 home automation control systems, and Digital Command Control type systems for Lionel and other AC model trains. When switching loads with the aid of a thyristor, a large amount of RFI can be generated unless some form of zero crossing switch is used. 
 Zero Crossing Switch Circuit Diagram

 The circuit shows a simple single transistor zero crossing switch. Rl and R2 act as a potential divider. The potential at their junction is about 10% of the ac voltage. This voltage level is fed, via R3, to the transistor`s base. If the voltage at this point is above 0, the transistor will conduct, shunting any thyristor gate current to ground. When the line potential is less than about 2 V, it is possible to trigger the thyristor. 
The diode Dl is to remove any negative potential that might cause reverse breakdown. If electrical power is to be …

Voice Switched Microphone Controlled Circuit Diagram

Build a simple voice switched microphone controlled circuit diagram. Voice activated control apparatus selectively connects one of a plurality of microphones to an audio line and inhibits all other microphones from capturing the line while the initial connection is maintained. In this circuit an electronic microphone feeds a bandpass filter circuit (IC1A), then feeds a comparator, which in turn drives Ql. Ql is a switch that conducts when audio from IC1B causes Dl, C4, R6, and R7 to bias it ON.
Voice Switched Microphone Controlled Circuit Diagram

Best Amplifier for signal supply Circuit Diagram

Best Amplifier for signal supply Circuit Diagram complicates the design process even further because of the reduced signal swings. This unity-gain follower amplifier has a CMOS p-channel input, an npn second-gain stage, and a CMOS inverter output. The IC building blocks are two CA3600E`s (CMOS transistor pairs) and a CA3046 npn transistor array. A zener-regulated leg provides bias for a 400-I`A p-channel source, feeding the input stage, which is terminated in an npn current mirror. 
 Best Amplifier for signal supply Circuit Diagram

 The amplifier voltage-offset is nulled with the 10-K!l balance potentiometer. The second-stage current level is established by the 20-K!lload, and is selected to approximately theist-stage current level, to assure similar positive and negative slew rates. The CMOS inverter portion forms the final output stage and is terminated in a 2-K!l load, a typical value used with monolithic op amps. Voltage gain is affected by the choice of load resistance value. The o…

High Speed Breaker Switch Circuit Diagram

This is the an electronic High Speed Breaker Switch Circuit Diagram. This 115 Vac, electronic circuit breaker uses the low drive power, low on resistance and fast turn off of the TMOS MTM15N50. The trip point is adjustable, LED fault indication is provided and battery power provides complete circuit isolation. The two `circuit breaker` terminals are across one leg of a full wave diode bridge consisting of D1-D4. 
 High Speed Breaker Switch Circuit Diagram
Normally, Q1 is turned ON so that the circuit breaker looks like a very low resistance. One input to comparator Ul is a fraction of the internal battery voltage and the other input is the drop across zeners D6 and D7 and the voltage drop across R1. If excessive current is drawn, the voltage drop across Rl increases beyond the comparator threshold (determined by the setting of R6), U1 output goes low, Q1 turns OFF, and the circuit breaker `opens.` When this occurs, the LED fault indicator is illuminated.

Simple Nonlinear Operational Amplifier Circuit Diagram

Simple Nonlinear Operational Amplifier Circuit Diagram nonlinear system, in contrast to a linear system, is a system which does not satisfy the superposition principle. Using resistor and transistor feedback elements, this operational amplifier circuit can be used as a nonlinear amplifier. R4 and R6 can be varied to change breakpoints, as required. 
Simple Nonlinear Operational Amplifier Circuit Diagram


Simple Light-operated switch Circuit Diagram

This is a Simple light-operated switch circuit diagram.This light sensitive circuit can operate a relay to switch on lamps or any AC loads when it senses darkness. 
 Simple Light-operated switch Circuit Diagram

 It is ideal to use as switch less night lamps. This circuit uses a flip-flop arrangement of Ql and Q2. Normally Ql is conducting heavily. Light on CDS photocell causes Ql bias to decrease, cutting it off, turning on Q2, removing the remaining bias from Q1. Reset is accomplished by depressing S1

Build a Precision Narrow Band Tone Switch Circuit Diagram

How to Build a Precision Narrow Band Tone Switch Circuit Diagram. This is a simple Precision Narrow Band Tone Switch Circuit Diagram. This signal tracker and lock detector combine to make a precision tone switch. Filter R3/R4/C2 determines signal capture and tracking range, as well as settling time. Max. VCO frequency: R& Min. VCO frequency: + Pin 9 voltage affects both. 
 Precision Narrow Band Tone Switch Circuit Diagram


The minimum at pin 9 is 0 V and the maximum at pin 9 is VDD. In the lock detector, the PC (phase comparator) outputs are pulses whose width is proportional to the phase difference between the two PC inputs. At lock up, the two PC outputs are almost mirror images. The output of IC1A remains low and IC1B is high. This lights LED1. If the loop is unlocked, the LED will not light.

A Charge Pump Circuit Diagram

A charge pump is a kind of DC to DC converter that uses capacitors as energy storage elements to create either a higher or lower voltage power source.This is a Positive input and negative output charge pump. The 74Cl4 IC is a self-oscillating driver for the MOSFET power switch. 
A Charge Pump Circuit Diagram


It produces a pulse width of 6.5 p,s at a repetition frequency of 100 kHz. When the MOSFET device is off, capacitor C is charged to the positive supply. When the power through the MOSFET switches on, C delivers a negative voltage through the series diode to the output. The zener serves as a dissipative regulator. Because the MOSFET switches fast, operation at high frequencies allows the capacitors in the system to be small.

Simple Proximity Detector Sensor Circuit Diagram

A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. This simple circuit is actuated by an increase in capacitance between a sensing electrode and the ground side of the line. The sensitivity can be adjusted to switch when a human body is within inches of the insulated plate used as the sensing electrode. Thus, sensitivity is adjusted with the 1 meg ohm potentiometer which determines the anode voltage level prior to clamping This sensitivity will be proportional to the area of the surface opposing each other.
Simple Proximity Detector Sensor Circuit Diagram

Simple Unity Gain Non-inverting Amplifier Circuit Diagram

In the world of electronic, gain is a measure of the ability of a circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output, by adding energy to the signal converted from some power supply. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system. 
 Simple Unity Gain Non-inverting Amplifier Circuit Diagram

 It is often expressed using the logarithmic decibel (dB) units ("dB gain"). A gain greater than one (zero dB), that is, amplification, is the defining property of an active component or circuit, while a passive circuit will have a gain of less than one. The same voltage level and impedance is also known as unity gain. This is a simple Biasing methods for an N-channel MOSFET to form a unity-gain non-inverting amplifier

Latch Debouncer Switch Circuit Diagram

This is a simple Latch Debouncer Switch Circuit Diagram In electronics latch is a circuit that has two stable states and can be used to store state information. Although this circuit uses a 74HC74, any CMOS variant of this flip-flop will work. IC1A acts as a true/ complement buffer. RI and R2 ensure that IC1A comes out of reset before the clock`s edge occurs. R3 applies IClA`s logic state to pins 1 and 3. When the switch closes, the next logic state stored on the capacitor transfers to the flip-flop`s reset and clock inputs. 
Latch Debouncer Switch Circuit Diagram 


Releasing the switch lets the capacitor charge to the next state via R4. IClA`s output is the LSB; IClB`s output is the MSB. Notice that the counter`s state advances when the switch is first pressed, rather than when it`s released; the latter is the case with many other switch-debouncing schemes. You can replace RI with a 22-pF capacitor to reduce the circuit`s sensitivity to parasitic effects. The addition of this capacitor …

Razor-sharp CW filter Circuit Diagram

The Razor-sharp CW filter Circuit Diagram consists of four stages of active bandpass filtering provided by two type-µ integrated-circuit dual op amps and includes a simple threshold detector (diodes Dl and D2) between stages 2 and 3 to reduce low-level background noise. Each of the four filter stages acts as a narrow bandpass filter with an audio bandpass centered at 750 Hz. The actual measured 3-dB bandwidth is only 80 Hz wide.
Razor-sharp CW filter Circuit Diagram

Build a Scanner Voice Squelch Circuit Diagram

This Scanner Voice Squelch Circuit Diagram detects the presence of audio (voice) on the output of a scanner. If the scanner stops on a `dead carrier` or noise, the circuit mutes the speaker to avoid annoying noise. Ul amplifies speech and drives rectifier D1/D2 and switch Ql. Comparator U3 drives speaker switch Ql and indicator LED1. Q2 completes the speaker path to ground. U2 is an audio amplifier to drive the speaker. R3 is a volume control. PL1 connects to the scanner speaker or to the headphone jack . 
Build a Scanner Voice Squelch Circuit Diagram

Best Audio Compressor Circuit Diagram

This Best Audio Compressor Circuit Diagram 2-band compressor splits the audio into high and low frequencies and allows independent adjustment of each. TVo active filters drive the two halves of dual voltage controlled amplifier/rectifier IC. Each section has a dynamic range greater than 100 dB. Compression gain slopes are adjustable from 2 to 25 for both audio bands. iB adjusts the threshold amplitude between the two bands. RK1 and R2/C2 control the compressor attack times (10 kfl and 2, respectively), while the 1.5- resistor in the integrator circuit controls the release line.
 Best Audio Compressor Circuit Diagram

Tunable Bandpass Filter Circuit Diagram

One of the difficulties in the design of higher-order tunable bandpass filters is achieving correct tracking of the variable resistors in the RC networks. The use of switched capacitor networks can obviate that difficulty, as is shown in this filter. The filter can be divided roughly into two stages: an oscillator that controls the electronic switches arid the four phase-shift networks that provide the filtering proper. 
Tunable Bandpass Filter Circuit Diagram


The oscillator, based on a 555, generates a pulsating signal whose frequency is adjustable over a wide range: the duty factor varies from 1:10 to 100:1. Electronic switches ESI through ES4 form the variable resistors whose value is dependent on the frequency of the digital signal. The operation of these switches is fairly simple. When they are closed, their resistance is about 60 ; when they are open, it is virtually infinitely high. a switch is closed for, say, 25% of the time, its average resistance is therefore 240…