Quote from: poynt99 on November 04, 2012, 02:39:41 PM
forest,

As an option, build one or two of these.

Beautiful work! It's nice that you go into the circuit operation theory as well as just providing schematics.

Printed a hard copy and placed in my electronics library!
Thanks again...
--TK

Thanks TK.

I enjoyed the design work and putting that doc together. Hopefully it has helped a few folks out.

I need to ask a question about power measurement in below circuit. Two loads A and B connected to 220 V AC. U1 is 3 volts and lets say I1 is 100 ma. U2 is 120 volts and I2 is 200 ma. This matches the real behaviour of this simple circuit: it halves source voltage and doubles the amps.
Power consumed by load A is 3 V * 0.1 A = 0.3 watts and power consumed by load B is 120 V * 0.2 A = 24 watts. Is power consumed by the system from the source 0.3 watts, 24 watts or something else ?

The way I see it is that when power is taken from point B there will be current increase seen at the source but not power increase because voltage changes only slightly. Hence current increase does not mean power increase in this case.

Forest, TheCell, can you fill in values of U1, U2, I1 and I2 in your setup ?

To make this self run would require use of DC-AC converter and then DC feedback from the output back to DC using diode bridge, possibly step it down without using trafo. Trafo would limit the amount of feedback. I don't have inverter available to make any tests but I think this is how TK makes feedback.

What is the "AC" voltage source?

If it is 120VAC or 220VAC, how can U1 be 3V?

You ought to try simulating this circuit for a better understanding of what is going on.

In my tests I used 220 V / 50 Hz mains.

Simulation does not match real world in this case.

We have seen replications from forest and TheCell, I picked up 3 V from forest's results. I think it was voltage drop across bulb A, so this needs verification. Bulb A shows almost no light while bulb B shows light.