AC to DC Schematic

1. Classic Plus and Minus DC Power Supply - produces both a positive 15v and a negative 15v from a 20vac wall adapter.
2. AC to DC Boost Converter with PFC - Implementation of a AC to DC Boost Converter with power factor correction.
3. Classic Linear 5v Supply Using 6.3vac Transformer - Circuit consists of an iron core transformer, a bridge rectifier, a filter capacitor and a voltage regulator.
4. AC-to-DC converter circuit utilizing IGBTs - AC-to-DC converter furnishing a regulated DC-output voltage from an AC-input supply voltage
5. Non-isolated Off-line AC to DC Power Supply - Efficient circuit can provide up to 100ma of a regulated 5 volts from an AC power.

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AC Inverter Low cost 12VDC to 120 220V

This inverter will sufficiently power any of your 115VAC (or 220VAC)small appliances। T1 choice of amperage is yours to make, but if you can salvage a heavy-duty unit from somewhere, use it. The least expensive method to get a larger transformer would be to remove the old 2000v primary and then re-wind an old microwave transformer. Most of these transformers are rated 1KW or better. Your local TV or Electronics repair shop may have one or dig one up from the dumpster. Just in case you dont know, micro-wave transformers can keep their charge (via the connected electronics) for a long time, so be careful!R1 and R2 are 10 ohm, wire-wound, and at least 5 watts. Wattage/cooling should be increased accordingly if you decide to beef up the output. For D1 and D2 you can use any power diode like the 1N4002 to 1N4005.If you live in Europe, Australia, or any other country with a 220VAC system, the only different is the transformer. This particular circuit can be constructed to handle up to 1 KiloWatt (1000 watt). If there is enough interest, I can modify this circuit to include a crow-bar circuit, battery backup, or more output in watts, or everything.The power output is determined by transformer T1, and power transistors Q1 & Q2. Assume a transformer of about 15A and the chosen transistors of 2N3055 (15A) type, the inverter can supply about 300 watts with the parts shown. If you are good with electronics all you have to do is replace the 2N3055s and T1 accordingly for more output. It is imperative to mount Q1 and Q2 on large coolribs. If you intend to beef everything up with a couple kilowatts a standard (5") cooling fan will also be required. If this is the case, the 2N3771 power transistor is a good choice at 30Amps. NTEs replacement, NTE181, is an improved version of the 2N3771 and carries 90volts instead of the 40 volts and can dissipate 200W instead of 2N3771s 150W.It is mandatory to include at least one suitable fuse and enclose this project in the correct casing. To be really safe you may want to include a primary and secundary fuse for your own protection. You are dealing with 120VAC or 220VAC at respectible amperage so be careful. The powercord also needs to be secured to prevent accidents.The 68uF Tantalum capacitors were chosen for their endurance. Normal electrolytic capacitors would overheat and explode. Somesort of cooling fan inside the project case may be a good choice, I myself use a ball-bearing cpu-fan from an old computer. New they dont cost that much either, about 3 bucks or so.

Since T1, and Q1/Q2 are NOT part of the PCB, these few parts can easily be used on a piece of Vero or experimenters board. Radio Shack and Tandy have these boards also available at a very reasonable price. The receptacle(s) on T1s output will be part of the case (obviously). I Just a small note about the 12 Volt battery, this circuit and others similar can draw huge amounts of current and will drain your battery in hurry so dont let your battery go dead! Thats why a wind/solar power combination would be an excellent future addition. For those interested in a PCB, I have included one below with a layout. As soon as I get my digital camera I will include pictures of the finished project. Read More

AC Mains Lamp Flasher Circuit Diagram

This electric lamp flasher which may be used as a warning light works directly on 230V-AC mains. - The diodes Dl to D4 in convert the alternating voltage into pulsating DC voltage. Components Rl, Cl, R2 and C2 form the timing circuit to control the flashing rate.  When the charged voltage across the capacitor C2 exceeds the neon’s (Nl) firing voltage, the neon fires and provides the  required triggering current to SCR. Then the SCR also fires and acts as a short, connecting the lamp across the AC mains. Finally, when the voltage across capacitor C2 falls below the maintaining voltage of the neon, the neon stops conducting and the SCR also returns to its non-conducting state, thus disconnecting the lamp from AC mains. The capacitor C2 starts charging again and the cycle repeats.

The lamp flashes in this circuit once every second. The rate can be varied, if required, by adjusting R2. The circuit of Fig. 2 is a simpler and a more economical arrangement. lt uses only one diode instead of four for rectification. ln fact, an SCR itself is a rectifier and power halving is done by it. The diode Dl is however required because without it the timing period will get disturbed during negative cycles. Incidentally, it helps to increase the reverse voltage ratings of the SCR and also protects the electrolytic capacitors by providing a proper polarity voltage. ln this arrangement the lamp flashes at a reduced brightness. Thus the circuit acts as a lamp flasher-cum-wattage halver.

 A 100W bulb used in this circuit, acts as a 50W lamp flasher. The lamp flasher may be light-controlled by adding an LDR across the timing capacitor C2. An LDR has high resistance in darkness and has little effect on the circuit functioning. When light falls on it (during day time), its resistance becomes sufficiently low to prevent the capacitor from charging to the neon lamp firing voltage. Instead of LDR a simple switch or reed relay contacts can also be used to short-circuit the capacitor C2 when the flasher is not required. Thus, by controlling low current path of triggering circuit, the high load current of the lamp can be switched on and off very conveniently. Caution: Since the flasher uses a SCR, RF interference can be a problem. lt is therefore advised to use a filter for eliminating the interference. 

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Ac to DC Converter Wiring diagram Schematic

This Ac to DC Converter Circuit Diagram includes a PMOS enhancement-mode FET input buffer amplifier, coupled to a classical absolute value schema which essentially eliminates the effect of the forward voltage drop across diodes D1 and D2. 

Ac to DC Converter Circuit Diagram

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