That is odd, especially as the V(p-p) is only 68pVThe thing that looks very strange on Mike's circuit (Post #17) is the 49 volts RMS at 13 Khz on the output.
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That is odd, especially as the V(p-p) is only 68pVThe thing that looks very strange on Mike's circuit (Post #17) is the 49 volts RMS at 13 Khz on the output.
Alec, can you post your .asc file?Strange. It simulates fine in LTspice. No sign of oscillation.
I simulated using NI Multisim, which uses the same Spice as LTspice.That is odd, especially as the V(p-p) is only 68pV. Don't know which simulator Mike uses, so perhaps I'm not interpreting the readout properly?
WikiPedia: said:NI Multisim (formerly MultiSIM) is an electronic schematic capture and simulation program which is part of a suite of circuit design programs, along with NI Ultiboard. Multisim is one of the few circuit design programs to employ the original Berkeley SPICE based software simulation.
I think I suggested .01uf caps. One thing about scope probes is that they have capacitance (usually small 15pf to gnd), so while using the scope, the probe capacitance may be enough to stop any oscillation. So during probing keep a meter connected to the output and look for a change when you apply your scope probe to the circuit. Does that make sense?Many thanks for your schematic and testing Mike. I'll be able to get my hands on some 0.1uf caps tomorrow and report back with my findings. My old scope doesn't show any osculations, but I don't believe it rules out the possibility. I'm visiting a friend who has a better scope so maybe I can try his scope out aswell. I'll post back with my findings asap.
I simulated using NI Multisim, which uses the same Spice as LTspice.
For some reason without the bypass caps, I was getting a convergence error, adding the caps corrected that. Hmm I had not noticed the AC signals being present. I will try and retrace my steps. Also I will place a signal viewer (Sim scope) with the current sim file, and see if I can view anything.
Yep that makes perfect sense. Tomorrow I'll grab some caps and I will have access to a better scope than I own. I'll test it with and without the caps and report my findings.I think I suggested .01uf caps. One thing about scope probes is that they have capacitance (usually small 15pf to gnd), so while using the scope, the probe capacitance may be enough to stop any oscillation. So during probing keep a meter connected to the output and look for a change when you apply your scope probe to the circuit. Does that make sense?
Party on
So what's the word EVO?Yep that makes perfect sense. Tomorrow I'll grab some caps and I will have access to a better scope than I own. I'll test it with and without the caps and report my findings.
Cool, let us know. Also as Alec suggested, double check your transistor pinouts especially the BD139, that one looks easy to flip backwardsHey Mike, just got my hands on the cap's couple hrs. Beleive me I I'm itching to install the cap's asap. At friends place right now. I should get a chance either tonight or tomorrow morning to install them. Bought some new 24v zener as well. Update asap![]()