Due to power supply problems in the modern age inverter has become necessity in human life.  The students have to face a lot of problems if there is no electricity in the examination days.  Thus by making this cheap inverter you can over come these difficulties.  You can run a fan and 2CFL [11Watt/230V]  tubes with this inverter.




This inverter is based on MOSFTER transistor. Its output is 100W. In the output stage two MOSFETS are used.  The equipments which are having load less than 100W can be used on this inverter, just as PCO, Telephone Booth, Electronics Weighing machine. IC KA3524, 4N35 & HA17358 are used in this inverter.  IC KA3524 is used in the inverter section.  From its pin no. 11 and 14, 50HZs frequency is produced.  This is amplified by the amplitute amplifier made of transistor BC557.  Its output is given to the gates of MOSFETs in the output section.  The output of the inverter is available at the secondary of inverter transformor after the switching action of MOSFETs.

IC 4N35 is a optocoupler IC and its job is to couple the sample of AC output voltage to the input of IC KA3524.  IC KA3524 is a pulse width modulated IC.  Due to this, with the help of 4N35 contant output voltage are available from the output.


With the help of operational amplifier built inside IC HA17358 battery is provided protection from overcharge.  Its job is to cut incase of overcharge and provide trickling charging to the battery.  Thus this small inverter does important jobs when compared to its capacity.


This inverter is based on MOSFET transistor.  Its capacity is 100W.  IN this inverter two MOSFETs are used.  Now-a-days bi-polar transistor 2N3055 is mostly not used in inverters because capacity of transistor is 50W.  Therefore,  for better output number of transistors are increased and they occupy more space. IC HA17358 is used for overcharge cut in the inverter.  In this IC there are two operational amplifiers and there are total 8 pins in two lines.  With this circuit the life of battery is increased.  The over charge battery cut indication is available with the glowing of LED1 [Red].  The over charge action automatically stops with relay RL2. IC SG3524N is used in the oscillator section to produce the 50Hz frequency.  The pin no. 15 of the IC gets the positive supply from RL1 and negative supply to pin no. 1 through the pin no. 4 of optocuppler IC [4N35].  Thus from contact no. 1,2,3 of the oscillator section the 50Hz frequency is connected to the terminals at the output section and output is available from the AC output socket.  Through this circuit the charging as well as inverting action automatically takes place.  In the circuit a 12V car battery is used.



  1. The MOSFET transistor should be carefully soldered.
  2. Take care that there is no shorting on PCB while soldering the components.
  3. First of all, check all the components so that they are OK as per the circuit.
  4. Take care of the polarity of diode while soldering it.
  5. Check the collector, base, emittor terminals of transistor before soldering.
  6. Clean the terminals of the parts before soldering.
  7. Use the proper size heatsync for the MOSFET transistor.