18W Mini Inverter (12v DC to 220v AC)

It is a premium quality 18w mini inverter circuit pcb board suitable for LED bulbs, CFL, Mobile charging, home made mini DIY inverter, etc.

This inverter circuit can easily convert the input 12v battery power to output 220v AC (up to 18 watt) where the size of the inverter is small, working with heat sink, easy to install in a small box.

The cost of this circuit board is normally sold in electronics spare parts shop at around Rs 60-150 (approx $1-2).

Specification of 18W mini inverter

Type: Voltage converter
Input voltage: DC 6V-12V
Input current: 1A-2.5A
Power output: AC220V 0.1W-18W
Protection: NA

Many online shopping sites (amazon, flipkart, ebay, etc.) claim that this inverter circuit produces 40 watt output, but I've measured 18 watt max. at dc 12v 2.5amp.

18W mini inverter Circuit diagram

Schematic of 18w mini inverter (12v dc to 220v ac) circuit shown below.

9W LED Inverter from Mobile Phone Charger.

Components used

The following components are used in the above diagram.

Transistors (Q1, Q2): 2SD1351 (you can also use CD880, 2N3055, 2SD1379)
Transformer core: EE40
Capacitor (C1): 25V 22µF
Capacitor (C2): 100V 47nF
Capacitor (C3): 1.6KV 4.7nF
Resistor (R1): 2.7KΩ
Inductor: 330µH 1A

Transformer windings details

Here a small EE-type ferrite core (no air gaps between them) transformer used to step-up the voltage.

The primary winding (L1) is 150 turns with 0.05mm copper wire, secondary windings (L2, L3) 7 turns each with 0.05mm copper wire, and feedback winding (L4) is 2 turns with 0.2mm copper wire.

Working principle of 18W inverter circuit

Inside the circuit, two NPN-transistor, a step-up transformer, and some capacitors, resistor, an inductor is used.

When the inverter circuit board gets the 12v DC input, transistors (Q1, Q2) convert the DC voltage to AC voltage with the high frequency where the inbuild transformer step-up the output voltage (approx. 220 volts ac) and that's powered the loads up to 18 watt.

Image source: www.electronicspices.com

Above, you can saw the demo of this inverter where an 18-watt LED bulb glows very brightly.

There's a dangerously high voltage at the output! You do everything at your own risk. The author does not take any responsibility for any of your harm.