4 output stages (5V/6V/9V/12V) DC regulated power supply circuit diagram

This is definitely an effective 4 output stage stabilized DC power supply for testing electronic circuit units. It provides good specification and stable output, and importantly, provides good results for most electronic circuits. The circuit gives you an audio-visual indication that if the PCB is under short circuit testing, the power circuit under testing can cut off the important components instantly from damage.

The circuit provides you with four different regulated DC outputs (12V, 6V, 9V and 5V), and an unregulated 18V DC output is selected by rotating switch S2. The results show that the selected output is connected to the output rail of an analog voltmeter.

The circuit works by providing 18V AC through a typical 18V-0-18V, 500mA step-down transformer. 18V DC is supplied by diodes D1 and D2, the smoothing capacitor C1 and the regulator IC (IC1) are coupled to a rectifier diode through the combination of IC4. The voltage regulator IC provides fixed, 12V, 6V, 9V and 5V regulated outputs, respectively added to the rotary switch contacts. This power supply is useful and efficient for loads requiring currents up to 200mA.

Behavior of Complementary Transistors T1 and T2 Event Circuit Power is On. The fully selected supply voltage is drawn at the collector transistor T2, suitable for the electrical load. LED3 means the presence of output voltage. The negative terminal of the PZ1 piezobuzzer is added through the output rail of LED2, so the piezobuzzer remains silent as its negative terminal is also present throughout the supply voltage (excerpt). If there is a short circuit on the output, LED2 lights up to activate the piezobuzzer.

A fuse fault indicator short circuit differentiates between output and input faults. It includes bi-color LED indication (LED1) and resistors R1 and R2. When the power fuse is intact, the red and green parts of the effective LED1 output a yellow light in parallel. When the fuse fails, the green LED goes out and the red LED light tells us fusion breakdown.

This circuit can be easily assembled on a universal PCB. Use a small heat sink for all ICs to dissipate the IC temperature correctly. The output voltage can be checked out on a voltmeter. Assmble and provide voltmeter, indicator light, rotary switch and enable circuit installation in a metal box/box.