So I went ahead and mashed up two circuits, using LTspice for initial nondestructive testing.
I took a Joule thief circuit that I know works (one of Colin55's projects), duplicated it and connected the two circuits together as one big multivibrator. (See attached .asc file and pictures.)
I really had no idea if this would even work. But to my total surprise, it did! But not in the way I was expecting (or, more accurately, hoping) it would work.
What I'm after is two Joule thieves connected as a multivibrator so that they alternately light, say for half a second each or so. If you look at the attached waveform, you can see that they are alternating, all right--on each cycle of the flyback (blocking) oscillator! Not at all what I'm after here, but a damned interesting quirk, at least to me. (The waveforms are taken from the transistor collectors/LED anodes.)
So what's going on here? And is there some easy way to make this work as I'd like? I'm thinking I'm close here, but I have the multivibrator rigged up wrong. (R3/C4 and R4/C3 are supposed to control the multivibrator cycles.)
I think this would be a really cool way to get two flashing LEDs out of a small supply. It would be even cooler if I could somehow run them both off the same transformer.
I took a Joule thief circuit that I know works (one of Colin55's projects), duplicated it and connected the two circuits together as one big multivibrator. (See attached .asc file and pictures.)
I really had no idea if this would even work. But to my total surprise, it did! But not in the way I was expecting (or, more accurately, hoping) it would work.
What I'm after is two Joule thieves connected as a multivibrator so that they alternately light, say for half a second each or so. If you look at the attached waveform, you can see that they are alternating, all right--on each cycle of the flyback (blocking) oscillator! Not at all what I'm after here, but a damned interesting quirk, at least to me. (The waveforms are taken from the transistor collectors/LED anodes.)
So what's going on here? And is there some easy way to make this work as I'd like? I'm thinking I'm close here, but I have the multivibrator rigged up wrong. (R3/C4 and R4/C3 are supposed to control the multivibrator cycles.)
I think this would be a really cool way to get two flashing LEDs out of a small supply. It would be even cooler if I could somehow run them both off the same transformer.