Negative Adjustable Power Supply Module by LM337

This power supply circuit module is a compact, easy to build. It uses negative variable power supply module. This power module is ideal for powering any application requiring a DC supply at current levels up to 1.5A.Diodes D1-4 form a bridge rectifier which converts the AC input voltage into a DC level. They also allow a DC input voltage to be connected either way around. Capacitor C1 smooths the DC output of the bridge whilst C2 provides high frequency decoupling. The LM337T is an adjustable regulator IC providing the desired output
voltage.

Diode D5 is reversed biased during normal operation and is used to protect the regulator if the output is connected to a voltage of the same polarity (eg battery). Diode D6 protects the regulator if a reverse polarity voltage is connected to the output.

Source:http://powersupplycircuit.blogspot.com
http://powersupplycircuit.blogspot.com/2009/02/negative-adjustable-power-supply-module.html

2-25V DC Power Supply Schematic by LM338

This DC power supply circuit uses a LM338 adjustable 3 terminal regulator to supply a current of up to 5A over a variable output voltage of 2V to 25V DC. It will come in handy to power up many electronic circuits when you are assembling or building any electronic devices. The schematic and parts list are designed for a power supply input of 240VAC. Change the ratings of the components if 110VAC power supply input is required.

As shown in the figure above, the mains input is applied to the circuit through fuse F1. The fuse will blow if a current greater than 8A is applied to the system. Varistor V1 is used to clamp down any surge of voltage from the mains to protect the components from breakdown. Transformer T1 is used to step down the incoming voltage to 24V AC where it is rectified by the four diodes D1, D2, D3 and D4. Electrolytic capacitor E1 is used to smoothen the ripple of the rectified DC voltage.

http://www.circuitpowersupply.com/circuitblog/2-25v-dc-power-supply-schematic-by-lm338/

Adjustable power supply 0.1V – 50V By CA3130 and 2N3055

This power supply circuit is highly stabilized that its output voltage will drop only 0.005% even though the load changes from 0 to 100%. Another excellent capability is that the output voltage will change only by 0.01% if the input voltage fluctuates. The capability if the circuit to be adjusted from 0.1V up to 50V is due to the application of opamp IC CA3130 in the circuit. Transistor T4 raises the output voltage to higher level, and at the same time it separates the lower level opamp from the high level of the output voltage. The reference voltage is supplied by IC1. It is a temperature compensated transistor array with 5 transistors. Four of these transistors are used as reference diodes and the fifth one sets the output impedance of the reference source.

The reference voltage is set through P1. The opamp CA3130 compares the reference voltage at its minus input to the output voltage at its input. The output voltage passes first through a voltage divider before it is fed into the plus input of the opamp. Transistors T1 and T2 work as darlington pair and amplifies the current. Transistor T3 functions as current limiter. The current limit is ajustable through P1, and the lowest current limit is 0.6 ampere. Once potentiometer P1 is set at maximum, current limiting is disabled.

Source: http://apowersupply.com/adjustable-power-supply-01v-50volts-3.html

dc power supply adjustable voltage 0-30 Volt at 2 Amp

When you want DC power supply Circuit , model to fine the value Voltage get 0-30V for apply general work. I thinks this circuit may is appropriate , because of give current get 2 Amp enough be usable experience all get comfortablely. By it uses ordinary equipment seek easy be IC LM723 for control voltage the level is all and systematically protect completely. And still have 2N3055 number transistors help boost current give tall fair the work.

The detail is other , you have can to see in original website http://www.next.gr