Design and production of practical and simple transistor adjustable voltage stabilized power supply

Electronics users often need a DC stabilized power supply to replace batteries as power supply when repairing radios and other practices.

The author imagined using commercially available components to design and make a simple transistor adjustable voltage stabilized power supply. DIYing it myself was quite successful. It goes without saying how happy I am.

This regulated power supply purchased the components shown in Figure 2 (omitted) according to the requirements of the schematic diagram in Figure 1. The circuit board can be made of fiberglass board as shown in Figure 3 (omitted) and Figure 4 (omitted) and processed with a small hacksaw. Then use an electric drill or hand drill to drill small holes at the positions shown in circle 4 (omitted). Use φ1.3mm hollow rivets to rivet and set aside. No rivets are required for threading holes and mounting holes. The finished product of the welded string is shown in Figure 5 (omitted) and Figure 6 (omitted).

With all the electronic parts available, the author has been thinking about what to use to make the casing. I thought of using a plastic lunch box as the outer shell, so I went to a small department store to test-purchase it. Finally, I saw a plastic condiment box (see Figure 7 (omitted)) that was more suitable. I bought it and made it. The most difficult thing to process is the outer casing. The author uses hand drills and files to process according to the component requirements or as a backup. If possible, you can spray white paint on the box to make it look more beautiful.

After the box body is processed, it can be assembled. You need to install the meter head and terminal posts first, because these two screws are on the lower level. If you don't install them first, if you install them on the top first, you won't be able to replace them on the bottom. It's not easy to assemble.

After the author has soldered the circuit board and connected it, he needs to implement the overall installation connection. Enthusiasts will succeed as long as they install according to the schematics and photos. Of course, the drawings and circuits must be carefully checked before powering on. Only after confirming that they are correct can the powering on test be carried out.

Generally, the installation is correct. After powering on, the voltage will appear on the voltmeter. The adjustable range of this power supply is about 2V~12.5V, and the effect is OK. Within the adjustable voltage range, the voltage drop at full load (at 0.3A) is within 5%, which meets the requirements of a simple adjustable regulated power supply. After listening to it after connecting it to the radio, it is very quiet, with no hum or modulated hum. It is like using a new battery. It is a good homemade electronic product. Worthy of imitation by electronics enthusiasts.

The other group is a rectified and filtered output with unregulated voltage and can be used as a backup power supply.