Low power power frequency inverter

Here is a simple small inverter power supply. It can continue to power 25W, 35W and other small soldering irons or low-power light bulbs when the AC power supply is cut off. For emergency use.

Transistors T1 and T2 (BC547) form a square wave multivibrator and output a 50Hz signal. This complementary output is sent from the collectors of T1 and T2 to the PNP Darlington driver stage composed of T3, T5 and T4, T6. And connect the output to the push-pull amplifier stage composed of T7 and T8.

The secondary of transformer X1 is connected to the collectors of push-pull amplifiers T7 and T8 through terminals 12-0-12. The center tap is connected to a 12v battery (7Ah), and the primary sends out 220v AC power for small power resistive loads.

When in use, just close the switch S1, and the transformer X1 will send out 220v AC voltage at its primary end, depending on the size of the load. Adjust the battery capacity, T5~T8 radiator size, transformer size, etc.