How to Build Your Own Power Inverter

Use two high-power transistors for this circuit.

A power inverter converts DC power into AC power. This conversion allows you to operate a household electrical device without the need of plugging it into a wall outlet. A hobbyist may choose to assemble a small power inverter. This power inverter may provide electrical power for a few small devices, such as radios, electric lamps or shavers.

Things You'll Need

• 12-volt battery
• 2 resistors, 820 Ohm
• 2 bipolar junction (PNP) transistors
• 1 center-tapped transformer, 24V
• 4 crimp-style ring terminals
• 1 microfarad electrolytic (polarized) capacitor
• Electrical pliers
• Electrical wire
• Electronic solder
• Soldering iron

Instructions

1. Cut eight pieces of wire, and strip half an inch of insulation from each wire end.

2. Solder one end of the first wire to one of the transformer terminals on the center-tap side. Solder one end of the second wire to the other transformer terminal on the center-tap side. Solder one end of the third wire to the center-tap.

3. Solder one end of the fourth wire to one of the transformer terminals on the non-center tapped side of the transformer. Solder one end of the fifth wire to the remaining terminal on the non-center tapped side of the transformer.

4. Place a ring terminal over the free end of the third wire, and crimp the terminal to the wire. Crimp one ring terminal each to the free ends of the fourth and fifth wires as well.

5. Twist together one end of the first wire jointly to the negative lead on the capacitor, the collector lead on the first transistor, and one of the leads on the first 820 Ohm resistor. Solder this connection.

6. Twist together one end of the second wire jointly to the positive lead on the capacitor, the collector lead on the second transistor, and one of the leads on the second 820 Ohm resistor. Solder this connection.

7. Twist together the free end of the first 820 Ohm resistor with one end of the sixth wire, and solder the connection.

8. Twist together the free end of the sixth wire with the base lead on the second transistor, and with one of the leads from the first 82 Ohm resistor. Solder the connection.

9. Twist together the free end of the second 820 Ohm resistor with one end of the seventh wire, and solder the connection.

10. Twist together the free end of the seventh wire with the base lead on the second transistor, and with one of the leads from the first 82 Ohm resistor. Solder the connection.

11. Twist together one end of the eighth wire jointly with the free leads from both 82 Ohm resistors, and with the emitter leads from both transistors. Solder the electrical joint.

12. Place a ring terminal over the free end of the eighth wire, and crimp the terminal to the wire.

13. Attach the ring terminal at the end of the third wire to the negative battery terminal. Attach the ring terminal at the end of the eighth wire to the positive battery terminal.

Tips & Warnings

• The voltage across the unoccupied ring terminals will be 120 volts AC.

References

• "Electronic Devices"; Thomas Floyd; 1996
• Electronic Circuits Archive: 12 to 120 Volt Inverter Circuit