So I've built one of Colin's (colin55) circuits that I think is pretty remarkable, his LED torch (B). It works really well.
But when I run a simulation of it in LTspice, there's a big discrepancy between his description of its behavior and what Spice reports. (See attached screenshot and Spice sim file.)
He claims it runs at 500kHz, but LTspice shows it as only about 150Hz. (Thanks to Eric Gibbs for showing me how to measure frequency with LTspice.)
Now, the inductances I used for L1 and L2 are only a guess (see my other threads here about trying to figure inductances). My homemade transformer is wound on a little bitty piece of ferrite broken off a larger piece (a cable loop). I suppose this could affect the frequency of the flyback operation, but not that grossly.
Anyhow, as always, very curious to hear explanations of what's going on here. Again, it's an amazing little circuit. Lights a "super-bright" LED really brilliantly on just one AA cell.
But when I run a simulation of it in LTspice, there's a big discrepancy between his description of its behavior and what Spice reports. (See attached screenshot and Spice sim file.)
He claims it runs at 500kHz, but LTspice shows it as only about 150Hz. (Thanks to Eric Gibbs for showing me how to measure frequency with LTspice.)
Now, the inductances I used for L1 and L2 are only a guess (see my other threads here about trying to figure inductances). My homemade transformer is wound on a little bitty piece of ferrite broken off a larger piece (a cable loop). I suppose this could affect the frequency of the flyback operation, but not that grossly.
Anyhow, as always, very curious to hear explanations of what's going on here. Again, it's an amazing little circuit. Lights a "super-bright" LED really brilliantly on just one AA cell.