Power Supply Adapter

This is a basic knowledge about how to generate very high DC Voltage from 240V main AC home supply. The design of this circuit is very simple.

This the rectifier circuit to convert AC supply become DC supply which not required diode, in other words, this is an diodeless rectifier, rectifier circuit without diodes.

This is a simple circuit design of 9V split power supply. This power supply circuit delivers plus and minus 9V to substitute the two 9V batteries. The rectifier circuit is certainly two separate full-wave rectifiers fed from the secondary of the transformer. One full-wave rectifier consists of diodes Dl and D2, which produce +9 V, and then the other consists of D3 and 4, which produce -9 V.

This is the design diagram of +15V / 1A regulated power supply using uA723. Circuit operation: The supply receives +20VDC from the rectifier / filter section (diode bridge). This is applied to pins 11 and 12 of the IC uA723, as well as to the collector of the 2N3055 series-pass transistor. The output voltage is simpled through R1 and R1, providing about 7V with respect to ground at pin 4. The reference terminal at pin 6 is tied directly to pin 5, the noninverting input of the error amplifier. For fine tuning output voltage, a potensiometer can be installed between R1 and R2. A 100 pF capacitor to pin 4 furnishes gain compesation for the amplifier .

This is the scheme design of -15V / 1A Regulated DC Power Supply . It used uA723 precision voltage regulator and TIP105 PNP Epitaxial Silicon Darlington transistor. The supply receives -20V from the rectifier/filted which is fed to the collector of the Darlington PNP pass transistor, a TIP105. The base drive to the TIP105 is supplied through resistor R5. The base of the TIP105 is driven from Vz terminal at pin 9, which is the anode of a 6.2V zener diode that connects to the emitter of the uA723 output control transistor.

This is the schematic diagram of voltage regulator circuit with pass transostor. The regulator is based regulator IC of LM317T. The LM317T output current can be raised by utilizing an additional power transistor (on circuit, it is 2N2955) to share a portion of the total current. The amount of current sharing is established with a resistor placed in series with the LM317 input and a resistor placed in series with the emitter of the pass transistor. In the above scheme design , the pass transistor will start conducting when the LM317 current reaches about 1 ampere, due to the voltage drop across the 0.7 ohm resistor. Current limiting happens at about 2 amperes for the LM317 which will drop about 1.4 volts across the 0.7 ohm resistor and make a 700 millivolt drop across the 0.3 ohm emitter resistor. Thus the total current is limited to about 2+ (.7/.3) = 4.3 amperes.

This is the high current dc power supply circuit with 5V output. The high current regulator utilizes an extra winding or a separate transformer to deliver power for the LM317 regulator so that the pass transistors can run closer to saturation and increase performance. For excellent performance the voltage at the collectors of the two parallel 2N3055 pass transistors ought to be near to the output voltage. The LM317 needs 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 10A), so a separate transformer and rectifier/filter circuit is utilized which is several volts higher than the output voltage.