(3) “Wimpy” – A PWM Limited FLIP FLOP DC – AC Inverter

A simple cap change got rid of any flicker, and I’m getting closer to finished. 12.75v * .3A = 3.83 Watts for a decent AC powered room light that can be replenished with a few sports solar chargers, or ideally a 10 watt solar panel. While i did not invent this BY ANY MEANS, there is no single component left the same as the circuits I started with, except the 2uF capacitance on the flip flop. Better choices and technique ABSOLUTELY can be found, but it works, and I’m a beginner, so it stands as a great learning experience. I’m calling this mod to the French Flip Flop inverter “Wimpy”. If you must, go ahead and knock it down, but it serves my needs, for now.

(2) RFP40N10 FETs, sources to PWM output, not common -12V
(2) MPSA06 NPNs, emitters to PWM output, not common -12V
1.2K resistors off NPN collectors to +12V
6.2K resistors off NPN base to +12V
2uF capacitors, tantalums I believe

555 PWM:
P1: common -12V
P2: to P6
P3: wiper on 100-500K pot
P4: Nothing, (but probably should be +12V)
P5: Nothing (but maybe should cap to -12V)
P6: tied to P2, then through a 400V red (polyester?) cap to -12V. As well, to the cathod end, and the anode end of two seperate 4148 diodes. On the other end of those diodes are the two remaining leads of the pot
P7: input side of RHRP3060 ultrafast 4-600 V diode
P8: to +12V

On the output side of the diode, 1K to +12V, also to gate of IRF3205.
Drain on IRF3205 to Source for Flip Flop Sources, NPN emitters
Source on IRF3205 to -12V common

Transformer is Hammond 166K18 18VCT 1.5A reversed step down
Lamps are 2 Watt AC LED bulbs, cheapies from Walmart, frosted type B’s

That’s pretty much it. It was all made from garbage so choices were arbitrary, and nonideal, but it works.

Pot will be replaced with 2 or 3 fixed resistors and a switch.


Post time: Feb-17-2018
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