Electric OU: Altoid 5: Reversed Current Flow at Load 2
AKA the LOADs of DOOM, Part 2 : The “LEDs of DOOM” test performed on Altoid at the load position. With one LED as normal, in the “proper” polarity in the load socket, the LED lights up, makes oscillations, but when it is reversed, it doesn’t light up and there are no oscillations, and the battery voltage shows on the Vbatt trace as normal. No oscs, no current flow in either direction, circuit is dead. With two LEDs “back to back”, that is, in anti-parallel, they both light up ! And the oscillations show a strong negative current portion, which will result in a definite “negative mean power” calculation from the Vcvr and Vbatt traces. The LED that is in the “correct” orientation, though… the one with anode towards the circuit’s positive rail… always glows more brightly than the other one. Even though an examination of the oscilloscope traces might naively indicate that the net power “flow” is in the negative direction…. the relative brightness of the LEDs should indicate, I think, that the real “balance of power” is actually in the positive direction, since that LED lights up brighter than the other one. And what does it mean in real life? (results with the various Zeners (3.3, 5.1, 6.6 V) in the Z position are normal, just lower f0 and less negative apparent power.)
