Converter 12 Vdc to 230 Vac or Inverter

As shown in the Inverter schema diagram obove , Its used as the oscillator stage astable multivibrator contained in IC1, a CMOS 4047 (this cult series 40xx series) by varying the resistance value of R1 trimmer (220 k total resistance) can vary the oscillation frequency of 40 Hz to 70 Hz square wave, phase shifted by 180 °,  Output pin 10-11 will drives two NPN transistors TR1-TR3, which in turn is fed to the TR2-TR4. 
Converter 12 Vdc to 230 Vac or Inverter Schematic 

The diodes DS2-DS3, mounted on the output transistors TR2-TR4 are used to protect against voltage surges appearing across the windings V 9 + 9 V transformer T1. For the transformer T1, I used an ordinary mains transformer (primary 230 V so) with a secondary dual 2 x 9 V. 

Parts List: 
R1 ……. 220 k trimmer 
R2 ……. 330 k 
R3 ……. 680 
R4 ……. 2.2 k 
R5 ……. 2.2 k 
C1 ……. 4.7 nF polyester 
C2 ……. 220 uF electrolytic 
DS1 ….. 1N4004 
DS2 ….. 1N4004 
DS3 ….. 1N4004 
DL1 ….. LED 
TR1 ….. BC184 NPN 
TR2 ….. NPN BDX53C 
TR3 ….. BC184 NPN 
TR4 ….. NPN BDX53C 
IC1 …… 4047 CMOS 
T1 …….. transformer sector 80 VA primary 230 V 0.35 A / Secondary 2 x 9 V 3.5 A 
S1 ……. switch 
Note : 

• Two final power TR2-TR4 should be mounted on the right size heatsink, otherwise they will overheat. You can choose from MJ4033 – MJ3007 or more, provided that the NPN.
• The maximum power output that can be used depending on the size of the core of the transformer T1, the VA is: with 50 VA can be taken in the secondary 230 V 0.2 A (current consumed by the end will be 4 A) with 90 VA can be taken on the secondary 230 V 0.4 a (current consumed by the end will be 7 A).
• To power the schema from the 12V battery, it will take over at least 1.8 millimeters in diameter, to avoid loss by Joule effect.