IC 555 Inverter Circuit with Triacs

This IC 555 inverter circuit with triacs makes use of an IC 555 for generating the oscillations and triacs for converting these oscillations into mains voltage through the transfomer.

The IC 555 is configured in it normal astable multivibrator mode for generating the required 50 Hz oscillations, and remember these oscillations can also be customized by adding a PWM pot with the IC 555 configuration.

OK, next the oscillation from the pin#3 of the IC 555 is given to a transistor flip flop stage using V1, and V2 which transforms the alternating high and low logics from the IC 555 into alternating flip flop pulses for the output power devices.

The output power devices here are not configured around power BJTs, mosfets, IGBTs rather ordinary triacs with the transformer.

Using triacs eliminates the restriction of having low secondary voltage transformers and allows higher voltage transformers such as 48-0-48V, or even 100-0-100V transformer which further means huge reduction in battery current and enabling compact inverter size even with high wattage designs.

The output from the V1, V2 stage is appropriately fed to the triac gates which instantly begin oscillating at the specified frequency.

The transformer can be any rated depending on the battery power and the load requirement.

No, the triacs would not latch even though this IC 555 inverter circuit using triacs operates with DC, because the two triacs react on the two winding of the transformer which generate back EMFs which are opposite to the other triacs and instantly breaks the conduction for the triac which is not in the triggered mode.

IC 555 inverter circuit using triacs

IC1 is IC555

V1, V2 = 2n2907

all diodes are 1N4007

R3, R4 = 27K

C3, C4 = 470nF

IC2 = 7806 IC

VT1 = 8amp/400V triacs

transformer= 30-0-30V/10amp

battery = 36V/25AH

wattage output = 300 watt