Tonight i went about rearranging the circuit,so as i could confirm the voltage across the primary winding in my DUT. As my scope and SG share a common ground(pain in the butt),i had to make the common rail of the circuit the positive,and the input to the transformer the negativesee modified circuit below. This allows me to measure the voltage across the coil before the 10 ohm CVR. Turns out my calculated voltage across the coil from previous tests,where i subtracted the voltage across the CVR from the total voltage,was correct,and the results are the same. The first scope shot shows the pulse input,which is a 20% duty cycle. The second scope shot shows the current and voltage trace,but where we now see a voltage across the coil by it self(yellow trace),and then the voltage across the coil and CVR series(blue trace). So this time when we make our current calculations,we subtract the coil voltage from the total voltage to get out voltage across the CVR. So V/in is an average of 1.8v for the 20% on time. I/in is 2.9v minus 1.8v= 1.1v across 10 ohms=110mA for our 20% on time. So P/in for the 20% on time is 198mW The 10 ohm CVR during this 20% on time dissipates 121mW So our average P/in is 198mW minus 121mW X 20% =15.4mW P/out is 22v across 15k ohms P/out = 32.26mW COP= 32.26/15.4 X 100 = 209.48% The COPs are consistent,no matter which way i take the measurements. Brad P.S Added the missing input pulse scope shotThanks Itsu for the reminder
« Last Edit: 20180830, 23:33:25 by TinMan »

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