I have some questions about this metronome (clicker) circuit found in Radio Shack's "Getting Started in Electronics" book. This circuit seems to be a popular one out on the internet(s) as far as metronome circuits go. Circuit: http://imgur.com/XyTasy3 The other night I said to myself if I can't understand this circuit completely I shouldn't bother trying any further with electronics (given all my studying thus far). So here we are... Here's what I've done so far... ================================================= I have successfully created the circuit on a breadboard. It works (and sounds) like a metronome adjustable via either the cap size or the pot. I get this on my scope by probing S (probe is grounded to battery negative): http://imgur.com/tRkuKDd (this is not actual.. i found this pic on internets but it's close... less frequent "hits" If I zoom in a lot, I see a nice waveform like this: http://imgur.com/Gi0g7te (that seems nice... like a nice gentle speaker friendly waveform) I have also somewhat (I think) successfully modeled/simulated it using Falstad's circuit designer: https://tinyurl.com/lnu7tas although the output on the virtual scope doesn't look like my real scope... and also, the only way I could get the cap to show discharged current flow was to get it to where it sometimes gives a convergence error... ================================================= Ok... so here's what I understand so far (I think!): NOTE: I've been very confused by previous simulation attempts... so bear with me please! I'm also a little confused as I get different behavior if I deselect the "trapezoidal approximation" setting on the C1 (which is currently deselected), etc. At one point I was even getting into "reverse active mode" on Q2 which really threw me off for a while. The basic idea is that C1 yanks back the speaker (thus creating a "wave"... I'm really simplifying here) once it is full and becomes essentially a short and sucks all the current from the source. And Q2 (via Q1) always want to push the speaker "out" (or whatever direction). I believe the cap fills first because it's essentially a short until it reaches a certain voltage at which time Q1 will become forward biased. Or does fbias occur on Q1 immediately? I'm confused if/how Kirchoff's laws come into play regarding when Q1 will become forward biased regarding when the cap gets to a certain level. Also, I wish I could tell what the charge field is at the connection between Q1 and Q2 but I'm lost there. Is it simply the voltage drop after Q2? I'm really confused about this. I apparently never see a speaker pushed out (positive bias) during non hits (idle time). Sorry so long. I just wanted to get this thread going as I've been procrastinating due to needing to put the links together. Thanks for any help you can give!!