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GATE 2014 Notification

GATE 2014 Notification poster has been released by IIT Kharagpur, the organizing institute for this year. The tentative examination schedule is also released. The exam will be conducted On Saturdays and Sundays between 1st February 2014 and 2nd March 2014. The exact schedule will be given on the GATE 2014 website.

GATE exam is a way to join in Post Graduate courses in Engineering like M.E, M.Tech or PhD in National level institute which is very crucial for engineering graduates. GATE 2014 will be organized by IIT Kharagpur.

What is New in GATE 2014 -

Gate 2014 will be conducted Online (Computer Based Test) all streams - AE, AG, AR, BT, CE, CH, CY, GG, MA, MN, MT, PH, TF, XE and XL, CS, EC, EE, IN , ME and PI .

GATE 2014 Eligibility :

The following categories of candidates are eligible to appear in GATE :

    Bachelor's degree holders in Engineering / Technology / Architecture / Pharmacy (Post - Diploma / Post-B.Sc / 4 years after 10+2) and those who are in the final year of such program…

Build a Bootstrapped Amp Current Source Circuit Diagram

Build a Bootstrapped Amp Current Source Circuit Diagram. This circuit responds to the difference between Vj and V2. Rq on sets gain. Resistors XR2 and (1 -X) R2 produce the bootstrap effect. These two resistors convert the circuit`s output voltage to a current. IC1 and IC2 are Burr-Brown OPA2107 or equal.

Bootstrapped Amp Current Source Circuit Diagram


Build a Bootstrapped Amp Current Source Circuit Diagram

Simple Battery charger Circuit Diagram

This is a simple Battery charger circuit diagram. A diac is used in the gate circuit to provide work for the signal being applied to the gate. R1 a threshold level for firing the triac. C3 and R4 is selected to limit the maximum charging cur-provide a transient suppression network Rl, rent at full Totation of R2. R2, R3, Cl, and C2 provide a phase-shift net.

Simple Battery charger Circuit Diagram



Simple Battery charger Circuit Diagram

Build a Remotely Adjustable Solid State High-voltage Supply Circuit Diagram

How to build a remotely adjustable solid state high-voltage supply Circuit Diagram. The output voltage changes approximately linearly up to 20 KV as the input voltage is varied from 0 to 5 V. The oscillator is tuned by a 5-0 potentiometer to peak the output voltage at the frequency of maximum transformer response between 45 and 55 kHz. 
The feedback voltage is applied through a 100-KO resistor, an op amp, and a comparator to a high-voltage amplifier. A diode and varistors on the primary side of the transformer protect the output transistor. The transformer is a flyback-type used in color-television sets. A feedback loop balances between the high-voltage output and the low-voltage input.

Remotely Adjustable Solid State High-voltage Supply Circuit Diagram




Remotely Adjustable Solid State High-voltage Supply Circuit Diagram

Build a 12v to 5v DC high efficiency SMPS buck converter using 34063 IC

This project converts 12v DC to a regulated 5v DC at up to 1.8 amps, suitable for driving a tablet computer from a 12v car battery in a power blackout etc.

The circuit for this buck converter is nothing original, basically it is the circuit from the 34063 IC datasheet, and all I did was to use an external PFET instead of the external PNP transistor shown in the datasheet. The external PFET allows currents up to a few amps at good efficiency, however I have used hard current limiting at 1.8A for safety and good performance in this prototype.

Energy conversion efficiency is very high due mainly to the choice of external components used with the cheap 34063 SMPS IC.


PCB layout.
The prototype was tested in hardware, please excuse the messiness. The layout is far from ideal, I did it this way to allow easy swapping of parts and just to be lazy, to save the effort of making a PCB. However it still works pretty good, and a proper PCB would improve performance a little bit.

PFET choice.

Precision full wave Rectifier Circuit Diagram

The circuit provides accurate full wave rectification. The output impedance is low for both input polarities, and the errors are small at all signal levels. Note that the output will not sink heavy current, except a small amount through the 10K resistors. Therefore, the load applied should be referenced to ground or a negative voltage. Reversal of all diode polarities will reverse the polarity of the output
Since the outputs of the amplifiers must slew through two diode drops when the input polarity changes, 741 type devices give 5% distortion at about 300 Hz.

Precision full wave Rectifier Circuit Diagram

400V-60W Push-Pull DC-DC Converter Circuit Diagram

The TL494 switching regulator governs the operating frequency and regulates output voltage. Switching frequency approximately 100 kHz for the values shown. Output regulation is typically 15% from no-load to full 60 W.


400V-60W Push-Pull DC-DC Converter Circuit Diagram


Simple Switching Regulator Circuit Diagram

This is the simple switching regulator circuit diagram. The LTC10432 switched-capacitor building block provides nonoverlapping complementary drive to the Ql to Q4 power MOSFETs. The MOSFETs are arranged so that Cl and C2 are alternately placed in series and then parallel. During the series phase, the + 12 V battery`s current flows through both capacitors, charging them, and furnishing load current. 
During the parallel phase, both capacitors deliver current to the load. Ql and Q2 receive similar drive from pins 3 and 11. The diode-resistor networks provide additional nonoverlapping drive characteristics, preventing simultaneous drive to the series-parallel phase switches. Normally, the output would be one-half of the supply voltage, but C1 and its associated components close a feedback loop, forcing the output to 5 V. With the circuit in the series phase, the output heads rapidly positive. 
When the output exceeds 5 V, Cl trips, forcing the LTC1043 oscillator pin, trace D, high; this tr…

Simple Hot-Lead Regulator Circuit Diagram

This Simple Hot-Lead Regulator Circuit Diagram derives 5 Vdc from 2-AA cells—even at their end-life voltages of 1.05 V, and is approximately 80% efficient, providing 5 V at 4 mA from 2.1 V at 11 mA. IC1 is manufactured by Maxim Integrated Products, Inc.


Hot-Lead Regulator Circuit Diagram


Flyback Converter Circuit Diagram

A low-current fly-back converter is used here to generate ±15 volts at 20 mA from a +5 volt regulated line. The reference generator in the SG1524 is unused with the input voltage providing the reference. Current limiting in a fly-back converter is difficult and is accomplished here by sensing current in the primary line and resetting a soft-start circuit.
Flyback Converter Circuit Diagram

Build a Full Wave Rectifier Circuit Diagram

This is the simple full wave rectifier circuit diagram.When equality of two equations shown in satisfied, full-wave output of circuit is symmetrical. The circuit uses a CA3140 BiMOS op amp in an inverting gain configuration.
Full Wave Rectifier Circuit Diagram

Simple Rapid Battery Charger Circuit Diagram

This is the simple rapid battery charger circuit Diagram. Rectified and filtered voltage from the 24 Vac transformer is applied to the LM723 voltage regulator and the npn pass transistor set up for constant current supply. 
The 470 ohm resistor limits trickle current until the momentary pushbutton (S2) is depressed, the SCR turns on and current flows through the previously determined resistor network limiting the charging current. The SCR will turn off when the thermal cutout circuit inside the battery pack opens up. 


Simple Rapid Battery Charger Circuit Diagram




Simple Dc/Ac Inverter Circuit Diagram

This dc-to-ac inverter is based on the popular 555. A 555 oscillator circuit drives a buffer amplifier consisting of Ql, Q2, and Q3. 
The circuit operates at 150 to 160 Hz. Tl can be a 6.3-V or 12.6-V filament transformer as applicable.The frequency can be changed by changing the values of Rl and/or Cl.

Simple Dc/Ac Inverter Circuit Diagram

Inverter as High Voltage low Current Source Circuit Diagram

The Inverter as High Voltage low Current Source Circuit Diagram is capable of providing power for portable Geiger counters, dosimeter chargers, high resistance meters, etc. The 555 timer IC is used in its multivibrator mode, the frequency adjusted to optimize the transformer characteristics. 
When the output of the IC is high, current flows through the limiting resistor, the primary coil to charge C3. When the output is low, the current is reversed. With a suitable choice of frequency and C3, a good symmetric output is sustained.

 Inverter as High Voltage low Current Source Circuit Diagram

Simple Crowbar Circuit Diagram

These circuits provide overvoltage protection in case of voltage regulator failure or application of an external voltage. Intended to be used with a supply offering some form of short circuit protection, either foldback, current limiting, or a simple fuse. The most likely application is a 5 V logic supply, since TTL is easily damaged by excess voltage. 
The values chosen in A are for a 5 V supply, although any supply up to about 25 V can be protected by simply choosing the appropriate zener diode. When the supply voltage exceeds the zener voltage +0 V, the transistor turns on and fires the thyristor. This shorts out the supply, and prevents the voltage rising any further. In the case of a supply with only fuse protection, it is better to connect the thyristor the regulator circuit when the crowbar operates. 
The thyristor should have a current rating about twice the expected short circuit current and a maximum voltage greater than the supply voltage. The circuit can be reset by either s…

Switch Selected Fixed Voltage Power Supply Circuit Diagram

This Switch Selected Fixed Voltage Power Supply Circuit Diagram can serve as a battery eliminator for various devices (such as tape recorders, small radios, clocks, etc.). Si selects a resistance that is predetermined to provide a preselected output voltage. In this circuit, various commonly used supply voltages produced by batteries were chosen, but any voltages up to the rating of Tl (approximately) can be produced by choosing an appropriate resistor. Remember to provide adequate heatsinking for Ul.

Switch Selected Fixed Voltage Power Supply Circuit Diagram


Switching Improves Regulator Efficiency Circuit Diagram

In this circuit, a full-wave bridge is switched to a full-wave center tap to reduce regulator dissipation. SCR D6 switches between configurations. When D6 is off, the circuit is an FWCT rectifier using Dl, D2, and D5. It applies 17 V plus ripple to the regulator input. 
The drop across the regulator supplies base drive to Q2. If Q2 is on, Ql is off, and D6 is off. If the regulator voltage drops below about 3 V, Q2 turns off, and turns Ql on, which turns on D6. This changes the circuit to an FW bridge using Dl through D4.
Switching Improves Regulator Efficiency Circuit Diagram


Charge Pool Power supply Circuit Diagram

It is usually desirable to have the remote transmitter of a 4 to 20 mA current loop system powered directly from the transmission line. In some cases, this is not possible because of the high-power requirements set by the remote sensor/transmitter system. In these cases, an alternative to the separate power supply is still possible. 
If the remote transmitter can be operated in a pulsed mode where it is active only long enough to perform its function, then a charge pool power supply can still allow the transmitter to be powered directly by the current loop. In this circuit, constant current II is supplied to the charge pool capacitor, CP, ~! the HA-5141 (where II ~ 3 mA). 
The voltage VI continues to rise until the output of the HA-5141 approaches + V, or the optional voltage limiting provided by Z2. The LM2931 voltage regulator supplies the transmitter with a stable + 5 V supply from the charge collected by CP. Available power supply current is determined by the duration, allowable vol…

Rosalind Franklin birthday

Rosalind Franklin,.
Molecular Biologist:

Rosalind Franklin (July 25, 1920 – April 16, 1958)

Rosalind Franklin, one the world’s most celebrated scientists, is also one of its most controversial. So controversial, in fact, that her work is the subject of a film, Race for the Double Helix, and two books, The Double Helix and Rosalind Franklin and DNA.

British molecular biologist Franklin was critical in discovering the structure of DNA. Her work has helped scientists understand how our genetic material is stored and copied. Yet when it was time to hand out Nobel prizes in 1962, they went to three male researchers, James Watson, Francis Crick and Maurice Wilkins. Franklin was shut out.

2.5A-1.25 To 25V Regulated Power Supply Circuit Diagram

This power supply uses an LM317J adjustable regulator and an MJ2955 pass transistor. Ql and U2 as well as Ul should be heats inked. A suitable heat-sink would typically be 4` 4` 1` fins, extruded type, because up to 65 W dissipation can occur. R8 and R9 should be 1% types or selected from 5% film types with an accurate ohmmeter. Capacitors are disc ceramic except for those with polarity marked, which are electrolytic. D1, D2—1-A, 100-PIV rectifier diode. DS1—Red LED. F1 —1,5-A, 3AG fuse in chassis-mount holder. J1, J2—Standard five-way binding post, one red, one black. M1—Milli-ammeter, 0-1 mA dc. Q1—NPN power transistor MJ2955 (Radio Shack) or equiv device with a + 70-V, 10-A, 150-W rating in a -204 case. R1, R2, R7—5-W wire-wound resistor. See Notes 3 and 4 for source, or, use 17 inches of no. 28 enam wire, single-layer wound, on a 10-KOhmhm, 1-W carbon-composition resistor for R1 and R7. For R2, use 36 inches of no. 30 enam wire on a 10-KOhmhm, 1-W carbon composition …

12V Latch Circuit Diagram

This circuit controls a solenoid by the operation of a single push-button switch. The circuit will supply loads of over 1 A and can be operated up to a maximum speed of once every 0.6 second. When power is first applied to the circuit, the solenoid will always start in its off position. Other features of the circuit are its automatic turn-off, if the load is shorted, and its virtually zero-power consumption when off.
12V Latch Circuit Diagram

50W Offline Switching Power supply Circuit Diagram

The schematic shows a 50W power supply with a 5-V 10-A output. It is a fly back converter operating in the continuous mode. The circuit features a primary side and secondary side controller will full-protection from fault conditions such as over current. After the fault condition has been removed, the power supply will enter the soft-start cycle before recommencing normal operation.
50W Offline Switching Power supply Circuit Diagram

High Voltage DC Generator Circuit Diagram

This circuit is fed from a 12-V de power supply. The input to the circuit is then amplified to provide a 10,000-Vdc output. The output of the up-converter is then fed into a 10 stage, high-voltage multiplier to produce an output of 10,000 Vdc.

High Voltage DC Generator Circuit Diagram

Super Universal Battery Charger Circuit Diagram

The Super Universal Battery Charger Circuit Diagram output voltage is adjustable and regulated, and has an adjustable constant-current charging circuit that makes it easy to use with most NiCad batteries. The charger can charge a single cell or a number of series-conoected cells up to a maximum of 18 V. 
Power transistors Ql and Q2 are conoected as series regulators to control the battery charger`s output voltage and charge-current rate. An LM317 adjustable voltage regulator supplies the drive signal to the bases of power transistors Ql and Q2. Potentiometer R9 sets the output-voltage level. A current-sampling resistor, R8 (a 0.1-!J, 5-W unit), is conoected between the negative output lead and circuit ground. For each amp of charging that flows through R8, a 100 mV output is developed across it. 
The voltage developed across RS is fed to one input of comparator U3. The other input of the comparator is connected to variable resistor RIO. As the charging voltage across the battery begins …

Simple split power supply circuit Diagram

This circuit utilizes the quasi-complementary output stage of the popular LM380 audio power IC. The device is internally biased so that with no input the output is held midway between the supply rails Rl, which should be initially set to mid-travel, is used to nullify any inbalance in the output. 
Regulation of Vout depends upon the circuit feeding the LM380, but positive and negative outputs will track accurately irrespective of input regulation and unbalanced loads. 
The free-air dissipation is a little over 1 watt, and so extra cooling: may be required. The device is fully protected and will go into thermal shutdown if its rated dissipation is exceeded. Current limiting occurs if the output current exceeds 1 A. The input voltage should not exceed 20 V.
Simple split power supply circuit Diagram

Simple Squib Firing Circuit Diagram

This is a Simple Squib Firing Circuit Diagram . Capacitor Cl is charged to +28 V through Rl and stores energy for firing the squib. A positive pulse of 1 mA applied to the gate of SCR1 will cause it to conduct, discharging Cl into the squib load XI. 
With the load in the cathode circuit, the cathode rises immediately to + 28 V as soon as the SCR is triggered on. DiodeD1 decouples the gate from the gate trigger source, allowing the gate to rise in potential along with the cathode so that the negative gate-to-cathode voltage rating is not exceeded. 
This circuit will reset itself after test firing, since the available current through Rl is less than the holding current of the SCR. After Cl has been discharged, the SCR automatically turns off—allowing Cl to recharge.
Squib Firing Circuit Diagram


Variable Zener Diode Circuit Diagram

The circuit behaves like a zener diode over a large range of voltages. The current passing through the voltage divider R1-R2 is substantially larger than the transistor base current and is in the region of 8 mA. The stabilizing voltage is adjustable over the range 5-45 V by changing the value of R2. The total current drawn by the circuit is variable over the range 15 mA to 50 mA.This value is determined by the maximum dissipation of the zener diode. In the case of a 250 mW device, this is of the order of 50 mA.
Variable Zener Diode Circuit Diagram

Ni-cad Charger Circuit Diagram

Ni-cad charger with current and voltage limiting. Lamp LI will glow brightly and the LED will be out when the battery is low and being charged, but the LED will be bright and the light bulb dim when the battery is almost ready. Ll should be a light bulb rated for the current you want (usually the battery capacity divided by 10). Diode D1 should be at least 1 A, and Z1 is a 1W zener diode with a voltage determined by the full-charge battery voltage minus 1 V. After the battery is fully charged, the circuit will float it at about battery capacity divided by 100 mA.
Ni-cad Charger Circuit Diagram


Power Supply Balance Indicator Circuit Diagram

This circuit uses two comparator pairs from an LM339N quad comparator; one pair drives the yellow positive (+)and negative (-)indicators, the other jointly drives the red warn LED3. The circuit draws its power from the unregulated portion of the power supply. The four comparators get their switching inputs from two parallel resistor-divider strings. Both~strings have their ends tied between the power supply`s positive and negative output terminals. 
The first string, consisting of R4, R5, and R6, divides the input voltage in half, with output taps at 0.5%. The other string, made up of R7, R8, and R9, also divides the input voltage in half, with taps at + lO%. The 0.5% R4/R5/R6 string drives the two comparators controlling the positive and negative indicators (LEDl and LED2). Their inputs are crossed so that LED2 does not fire until the positive supply is at least 0.5% higher than the negative; the positive indicator does not go off until the negative supply is at least 0.5% higher than…

Offline Converter Circuit Diagram

This nonisolated, unregulated, minimum component converter fills the void between low-power zener regulation and the higher power use of a 60-Hz input transformer. It is intended for use where)`er a nonisolated supply can be used safely. 
The circuit operates~by conducting only during the low-voltage portion of the rectified sine wave. Rl and D2 charge Cl to approximately 20 V, which is maintained by Ql. This voltage is applied to the gate of Q2, turning it on. When the rectified output voltage exceeds the zener voltage ofD4, Ql turns on, shunting the gate of Q2 to ground, turning it off.
Offline Converter Circuit Diagram


Super High Power Portable TV and FM Jammer Circuit Diagram

This is the Super High Power Portable TV and FM Jammer Circuit Diagram. There are still neighbors that keep annoying you by having loud the TV or the radio? Well I have you the solution. In fact all neighborhood will face your jamming waves at their TVs and radios, so be careful. 
This Jammer is the improved version of the old `TV and FM jammer schematic` with the difference of much higher power. Many of you where asking for a stronger and wider effect but to be as portable as can be. Looking at the schematic you can see that, only the parts are changing keeping the basic circuit intact. Have in mind that this version needs heat sink and antenna to keep the transistor alive.
Super High Power Portable TV and FM Jammer Circuit Diagram



The power source comes from three 9 volt batteries in series, so we use 27 volts at input, and we get a power full 2,5 Watts at output.   You are going to need 70cm to 2 meter simple wire antenna.   As for the transistor Q its the 2N3553. Its a R…

Power Supply Monitor-Memory Protector Circuit Diagram

This Power Supply Monitor-Memory Protector Circuit Diagram detects low-voltage supply conditions, down to 0.6 V. Dl sets the trip point of the circuit. The circuit is useful to protect memory circuits from accidental writes in the event of power-supply low-voltage conditions, which cause other circuits to turn off, etc. Response time is about 700 ns. R6 provides some hysteresis to ensure clean transitions.
Power Supply Monitor-Memory Protector Circuit Diagram

13.8Vdc 2A Regulated Power Supply Circuit Diagram

This 13.8Vdc 2A Regulated Power Supply Circuit Diagram consists of step-down transformer Tl, a full-wave rectifier bridge (D1 through D4), and a filtering regulator circuit made up of Cl, C2, Rl, R2, R8, D5, and Ql, When 120 Vac is provided, the neon-lamp assembly LI lights up, and transformer Tl changes 120 Vac to about 28 Vac. 
The rectifier bridge, )1 through D4, rectifies the ac into pulsating dc, which is then filtered by Cl. Capacitor Cl acts as a storage capacitor. Zener diode 1)5 keeps the voltage constant across the base of Darlington regulator Ql, causing constant voltage across resistor R3 and the (+) and (-) output terminals, where the load is connected. Fuse F2 is used to open (blow), if the current through the output terminals is too high. Make sure to take proper precautions when using projects powered by 120 Vac.
 13.8Vdc 2A Regulated Power Supply Circuit Diagram


Battery Charge-Discharge Indicator Circuit Diagram

This Battery Charge-Discharge Indicator Circuit Diagram monitors car battery voltage. It provides an indication of nominal supply voltage as well as low or high voltage. RV1 and RV2 adjust the point at which the red/yellow and yellow/green LEDs are on or off. For example the red LED comes on at 11V, and the green LED at 12V. The yellow LED is on between these values.

Battery Charge-Discharge Indicator Circuit Diagram

100Khz Multiple Output Switching Power Supply Circuit Diagram

The 100Khz Multiple Output Switching Power Supply Circuit Diagram uses two VN4000A 400-V MOSPOWER FETs in a half-bridge power switch configuration. Outputs available are + 5 Vat 20 A and ±15 V (or ±12 V) at 1 A. Since linear three-terminal regulators are used for the low-current outputs, either ±12 V or ±15 V can be made available with a simple change in the transformer secondary windings. 
A TU94 switching regulator IC proVides pulse-width modulation control and drive signals for the power supply. The upper MOSPOWER FET, Q7. in the power switch stage is driven by a simple transformer drive circuit. The lower MOS. Q6, since it is ground referenced. is directly driven from the control !C.
 100Khz Multiple Output Switching Power Supply Circuit Diagram

High Voltage Regulator Circuit Diagram

The High Voltage Regulator Circuit Diagram delivers 100-V at 100 mA and withstands shorts to ground. Even at 100 V output, the LT317A functions in the normal mode, maintaining 1.2 V between its output and adjustment pin. Under these conditions, the 30-V zener is off and Ql conducts. When an output short occurs, the zener conducts, forcing Q1`s base to 30 V. 
This causes Q1`s emitter to clamp 2 VnEs below Vz. well within the V.w VouT rating of the regulator. Under these conditions, Q1, a high-voltage device, sustains 90 V-VcE at whatever current the transformer specified saturates at 130 mA, while Q1 safely dissipates 12 W. If Q1 and the LT317 A are thermally coupled, the regulator will soon go into thermal shutdown and oscillation will commence. 
This action will continue, protecting the load and the regulator as long as the output remains shorted. The 500-pF capacitor and the 10 0/0.02 11F damper aid transient response and the diodes provide safe discharge paths f…

Tracking Dual Output Bipolar Supply Circuit Diagram

This Tracking Dual Output Bipolar Supply Circuit Diagram is useful for a bench supply in the lab. Separate or tracking operation is possible. The regulators should be properly heatsinked. Tl is a 24-Vac wall transformer of suitable current capacity. 
Tracking Dual Output Bipolar Supply Circuit Diagram 

Current to Voltage Converter Circuit Diagram

A filter removes the dc component of the rectified ac, which is then scaled to RMS. The output is linear from 40 Hz to 10 kHz or higher.
 Current to Voltage Converter Circuit Diagram

Hand Held Transceiver dc Adapter Circuit Diagram

This Hand Held Transceiver dc Adapter Circuit Diagram provides a regulated 9-V source for operating a Kenwood TR-2500 hand-held transceiver in the car. The LM317T`s mounting tab is electrically connected to its output pin, so take this into account as you construct your version of the adapter. The LM317T regulator dissipates 2 or 3 W in this application, so mount it on a 1-x -2-inch piece of `is-inch-thick aluminum heatsink. 
 Hand Held Transceiver dc Adapter Circuit Diagram

Precision Voltage Inverter Circuit Diagram

This Precision Voltage Inverter Circuit Diagram allows a reference to be inverted with 1 ppm accuracy, features high input impedance, and requires no trimming.
Precision Voltage Inverter Circuit Diagram 


Super Ni-Cd Battery Charger 12-18V Circuit Diagram

A clever charger circuit that safely can charge any Ni-Cd battery. Offers charge current sellection, polarization detection and protection and the ability to connect many batterys in siries. Ni-Cd bateries can be recharged more than 1000 times before become useless. the charging current shoud be the 1/10 of the (Ah) of the battery. The bateries need 14 hours to be fully charged.Swhitch S2 is the current selection as folows: 50mA, 200mA and 400mA. LED D10 is the indicator for proper batery connection and/or wrong polarity checking. LED D9 is the charging indicator. The transformer is a 220V/2x12V 0.5A. 
Super Ni-Cd Battery Charger 12-18V Circuit Diagram






 PARTS LIST R1,R4,R5=10K  R2,R3=100K  R6,R8,R10=1K  R7=820  R9=100  R11=15  R12=3,9  R13=1,8  C1=1000uF/40v  C2=470pf  D1-D4,D6=1n4001-7 D7,D8=1n4148  D9,D10=LED IC=741  TR1=BC548  TR2=BD137  TR3=2N3055
Datasheet file1: Click here to download LM741.pdf datasheet. Datasheet file2: Click here to download BC548.pdf datasheet. Datasheet file3: Click …

Basic single-supply voltage regulator Circuit Diagram

The circuit uses a CA3140 BiMOS op amp capable of supplying a regulated output that can be adjusted from essentially 0 to 24 volts. The circuit is fully regulated.

Basic single-supply voltage regulator Circuit Diagram


Simple 8V From 5V Regulator Circuit Diagram

If you have trouble locating an 8-V regulator, although they are commonly available,a 5-V unit can replace it by connecting the regulator, as is shown here. 
Simple 8V From 5V Regulator Circuit Diagram


Over voltage Protection for Logic Circuit Diagram

Zener diode ZD1 senses the supply, and should the supply rise above 6 V, Ql will turn on. In turn, Q2 conducts clamping the rail. Subsequent events depend on the source supply. It will either shut down, go into current limit or blow its supply fuse. None of these will damage the TTL chips. The rating of Q2 depends on the source supply, and whether it will be required to operate continuously in the event of failure. Its current rating has to be in excess of the source supply. 

 Over voltage protection for logic Circuit Diagram

Build a high-volt supply Circuit Diagram

A light dimmer, a 1 µf capacitor and a 12 V car ignition coil form the simple line powered HV generator. The current in the dimmer is shown in Fig. B. At times tp t2, set by the dimmer switch, the inner triac of the dimmer switches on, and a very high and very fast current pulse charges the capacitor through the primary of the induction coil. 
Then at a rate of 120 times per second for a 60 Hz line, a very high voltage pulse appears at the secondary of the coil. To obtain an HV dc output, use a voltage doubler. Dl and D2 are selenium rectifiers (TV 18 Siemens or ITT) used for the supply of television sets. High value output shock protection resistors, R, are recommended when suitable. 
Build a high-volt supply Circuit Diagram