Control 12V to 24V DC- DC Converter

This simple circuit is a DC-DC converterthat converting up 12V source to a 24V. It can be used to run radios,small lights, relays, horns and other 24V accessories from a 12Vvehicle with a maximum draw of about 800mA.

 The Schematic 12V to 24V DC- DC Converter

This DC-DC Convertercan be used to charge one 12V battery from another, or step up thevoltage just enough to provide necessary overhead for a 12V linearregulator. Using one op-amp as a square wave oscillator to ring aninductor and another op-amp in a feedback loop, it won't drift aroundunder varying loads, providing a stable 24V source for manyapplications. With a wide adjustment in output this circuit has manyuses.

Parts List
R1-R4,R7-R8 100K 1/4W Resistor
R5 470 Ohm 1/2W Resistor
R6 10K Linear Pot
C1 0.01uF Mylar Capacitor
C2 0.1uF Ceramic Disc Capacitor
C3 470uF 63V Electrolytic Capacitor
D1 1N4004 Rectifier Diode
D2 BY229-400 Fast Recovery Diode See Notes
Q1 BC337 NPN Power Transistor
U1 LM358 Dual Op Amp IC
L1 See Notes
MISC Board, Wire, Socket For U1, Case, Knob For R6, Heat sink for Q1

DC- DC Converter Notes
1. R6 sets the output voltage. This can be calculated by Vout = 12 x (R8/(R8+R7)) x (R6B/R6A).
2. L1 is made by winding 60 turns of 0.63MM magnet wire on a toroidal core measuring 15MM (OD) by 8MM (ID) by 6MM (H).
3.D2 can be any fast recovery diode rated at greater then 100V at 5A. Itis very important that the diode be fast recovery and not a standardrectifier.
4. Q1 will need a heat sink.

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Control Variable DC Power Supply With LM317

This DC power supply circuit is adjustable using IC Voltage Regulator LM317. LM317 is a versatile and highly efficient 1.2-37V voltage regulatorthat can provide up to 1.5A of current with a large heat sink. It'sideal for just about any application. This was my first workbench powersupply and I still use it.

Since LM317 is protectedagainst short-circuit, no fuse is necessary. Thanks to automaticthermal shutdown, it will turn off if heating excessively. All in all,a very powerful (and affordable!) package, indeed.

Although voltage regulator LM317 is capable of delivering up to 37V, the DC power supplyoutput circuit here is limited to 25V for the sake of safety andsimplicity. Any higher output voltage would require additionalcomponents and a larger heat sink.

Make sure that theinput voltage is at least a couple of Volts higher than the desiredoutput. It's OK to use a trim-pot if you're building a fixed-voltagesupply.

Problems:
Follow all the safety precautions when working with mains voltage. Insulate all connections on the transformer.

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Control 6A, 5 Volt Power Supply

The standard variable voltage regulator type LM150 is fairly easily available, but at times its out, which is limited to about 3 amperes, may prove to e a limiting factor to its utility, nut the simple modification describe here allows the to be enhanced to about 6 amperes. The circuit has inbuilt safe area protection and thermal overload protection.The circuit has been tested for lone regulation of the order of about 0.01% volt and load regulation of about 0.1% volt.
The circuit works on principle similar to the compact 10A power supplies. The two LM150 regulators are wired in parallel mode with  IC3 which controls them. The output voltage is given by the relation
Vout=1,25x(1+R5/R4) volts. The input voltage may lie anywhere in the range of 12 to 30 volts.

The IC must be adequately heat sinked in order to obtain full output current all over the operative temperature range 

The circuit 6A, 5 volt Power Supply

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Control 32W HiFi Amplifier circuit based on TDA2050

This is a High Fidelify (Hi-Fi) amplifier circuit based on single IC TDA205. This is a mono channel audio amplifier. You need to build the same circuit for stereo channel.

TDA2050 Description:
The TDA 2050 is a monolithic integrated circuitin Pentawatt package, intended for use as an audio class AB audioamplifier. Thanks to its high power capability the TDA2050 is able toprovide up to 35W true rms power into 4 ohm load @ THD =10%, VS = ±18V,f = 1KHz and up to 32W into 8ohm load @ THD = 10%, VS = ±22V, f = 1KHz.Moreover, the TDA 2050 delivers typically 50W music power into 4 ohmload over 1 sec at VS=22.5V, f = 1KHz.
The high power and verylow harmonic and crossover distortion (THD = 0.05% typ, @ VS = ±22V, PO= 0.1 to 15W, RL=8ohm, f = 100Hz to 15KHz) make the device mostsuitable for both HiFi and high class TV sets.

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Control High Current Regulated Supply

The high current regulator below uses an additional winding or a separate transformer to supply power for the LM317 regulator so that the pass transistors can operate closer to saturation and improve efficiency. For good efficiency the voltage at the collectors of the two parallel 2N3055 pass transistors should be close to the output voltage. The LM317 requires a couple extra volts on the input side, plus the emitter/base drop of the 3055s, plus whatever is lost across the (0.1 ohm) equalizing resistors (1volt at 10 amps), so a separate transformer and rectifier/filter circuit is used that is a few volts higher than the output voltage. The LM317 will provide over 1 amp of current to drive the bases of the pass transistors and assumings a gain of 10 the combination should deliver 15 amps or more. The LM317 always operates with a voltage difference of 1.2 between the output terminal and adjustment terminal and requires a minimum load of 10mA, so a 75 ohm resistor was chosen which will draw (1.2/75 = 16mA). This same current flows through the emitter resistor of the 2N3904 which produces about a 1 volt drop across the 62 ohm resistor and 1.7 volts at the base. The output voltage is set with the voltage divider (1K/560) so that 1.7 volts is applied to the 3904 base when the output is 5 volts. For 13 volt operation, the 1K resistor could be adjusted to around 3.6K. The regulator has no output short circuit protection so the output probably should be fused.

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Control TDA7295, 80W Audio Amplifier

Below is a 80W amplifier circuit is constructed by using a power ICTDA7295. With a very simple design, makes this circuit very easy tobuild. TDA7295 has many features to support your audio system, the most important is that the IC has very low distortion and very low noise feature.

The TDA7295 is a monolithic integrated circuit in Multiwatt15package, intended for use as audio class AB amplifier in Hi-Fi fieldapplications such as home theatre and topclass TV. The wide voltagerange and to the high out current capability make the TDA7295 able tosupply the highest power into both 4W and 8W loads even in presence ofpoor supply regulation, with high Supply Voltage Rejection.
The built in muting function with turn on delay simplifies the remote operation avoiding switching on-off noises.

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Control 10W Audio Amplifier circuit based on TDA1910

Simple and cheap, that's the advantage of this circuit. Although the output power is not high but audio quality is good, because TDA1910 has a very low noise feature. This circuit suitable for use as a student project.

About TDA1910:
The TDA1910 is a monolithic integrated circuit in MULTIWATT® package, intended for use in Hi-Fi audio power applications, as high quality TV sets.
TheTDA 1910 meets the DIN 45500 (d = 0.5%) guaranteed output power of 10Wwhen used at 24V/4W. At 24V/8W the output power is 7W min.
TDA1910 Features:

• muting facility
• protection against chip over temperature
• very low noise
• high supply voltage rejection
• low “switch-on” noise.

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