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Variable DC/AC Power Supply Circuit Designs

Use these free variable power supply circuit designs to build you own adjustable power supply for your workshop or other use. We love these!

LM317 1-25 Volts Variable DC 1.5 Amp Power Supply
3 Comments - in DC Power Supplies
An extremely simple and cheap DC power supply with variable voltage (1.2-25 Volts) control. The circuit uses an LM317 integrated voltage regulator Ic.
2N3055 Variable DC Voltage Power Supply
0 Comments - in DC Power Supplies
Variable-voltage DC power supply circuit. The output DC voltage is adjustable from 0.7-24V, with current limiting range from 50mA up to 2 Amps. Main transistor is the 2N3055.
Variable DC Power Supply (1-30 Volts, 5 Amps). LM338K Regulator
0 Comments - in DC Power Supplies
A very simple variable power supply with a DC output voltage adjustable from 1-3- Volts, with a maximum DC current of 5 Amps. Uses LM338 DC voltage regulator IC.
Photo: Hobby Power Supply Kit using LM7805 Hobby Power Supply Kit using LM7805
This is a practical battery eliminator for your projects. This is a basic power supply using two 7805 regulators; input up to 20 VAC from a transformer. There are two outputs; one regulated at 5 VDC, and the other one is variable. Includes plastic case. T
Photo: LM317 Variable Power Supply LM317 Variable Power Supply
A very basic power supply that can be adjusted over a range of about 1.5 to 35 volts DC. If you add a heat sink (included), you can run it as hot as 2 Amps output; otherwise about 60 mA @ 12 volts. This is a text book circuit using an LM317, which is a 3
Photo: Variable Power Supply Kit Variable Power Supply Kit
A handy portable power supply with a variable output voltage of 15VDC. Mounted in a rugged bakelite case.
Photo: Bench AC/DC Power Supply Kit Bench AC/DC Power Supply Kit
Build this educational Deluxe Bench DC Power Supply Kit
Photo: Bench DC Power Supply Kit Bench DC Power Supply Kit
Build this educational Deluxe Bench DC Power Supply Kit
Photo: Positive Adjustable Power Supply Positive Adjustable Power Supply
Compact positive (K124) and negative (K125) adjustable power supply +/-
Photo: Variable Power Supply with Transformer Variable Power Supply with Transformer
A very basic power supply that can be adjusted over a range of about 1.5 to 35 volts DC. If you add a heat sink (included), you can run it as hot as 2 Amps output; otherwise about 60 mA @ 12 volts. This is a text book circuit using an LM317, which is a 3
Photo: 3 Amp Variable DC Power Supply 3 Amp Variable DC Power Supply
Provides 3 amps current at 3-30 Volts DC. Reduces ripple voltage to almost non-existant.
Photo: Negative Adjustable Power Supply Negative Adjustable Power Supply
Compact negative adjustable power supply