A bench power supply is an essential tool for all electronics hobbyists. Building one is the right of passage for every electrical engineer. My BCIT program included a 4-week course ELEX 1102: Electronics Fabrication Tools and Techniques, in which we built a very basic bench power supply.
The DC Power Supply provides three DC voltage outputs when powered by a 120VAC 60Hz source. The rated DC output voltages are +5VDC (fixed), -15VDC (fixed), and +20VDC (variable). The rated current at each output is 1A.
We learned soldering skills in this course. We also learned how to use Altium Designer to design our own PCBs. In another course I learned how to use AutoCAD and designed the body for this power supply (reference design provided by BCIT).
Schematic diagram, interconnect diagram, and body CAD…
BOM (Electrical)
| Ref Des | Value/PN | Description | Pkg | Qty |
|---|---|---|---|---|
| C1, C2 | 3300µF, 20% | 25V, Al electrolytic | Radial | 2 |
| C3, C5 | 0.1µF, 20% | 50V, Al electrolytic | Radial | 2 |
| C4, C6 | 1µF, 20% | 50V, Al electrolytic | Radial | 2 |
| C7 | 2.2µF, 20% | 50V, Al electrolytic | Radial | 1 |
| D1, D2, D3, D4 | 1N4005 | 1A, 600V, General Purpose | DO-41 | 4 |
| D5 | - | Pilot light, LED, Red | - | 1 |
| F1 | 375mA, 250V | Cartridge, Glass, Time delay | - | 1 |
| J1 | - | Banana jack, Red, Nut | - | 1 |
| J2 | - | Banana jack, White, Nut | - | 1 |
| J3 | - | Banana jack, Violet, Nut | - | 1 |
| J4 | - | Banana jack, Black, Nut | - | 1 |
| P1 | 125V, 10A | 1.8m, 18 AWG/3C Grey | - | 1 |
| R1 | 10R, 5% | 10W | Axial | 1 |
| R2, R4 | 390R, 5% | 1/4W | Axial | 2 |
| R3 | 5K, 10% | 1/2W, Linear | - | 1 |
| S1 | 120V, 5A | SPST, Round rocker, Dot | - | 1 |
| T1 | 33VCT/1A | 33V, Center tapped, 1A | - | 1 |
| U1 | 7805 | Regulator, 1A, Fixed, 5V | TO220-3 | 1 |
| U2 | 317 | Regulator, 1.5A, Variable | TO220-3 | 1 |
| U3 | 7915 | Regulator, 1A, Fixed, 15V | TO220-3 | 1 |
