"Dave" schreef in bericht
netamerica...
Posted a while back about a project I am trying to concoct- an intercom
for my front door- and have made some progress. Unfortunately I hit a
speed bump when I added transistor Q4. Now it only gives me noise at the
output, and lots and lots of that. Capacitors are all 100uF 35V, which I
am thinking may be the problem (maybe the last couple need to be 50 or
75V?) Originally thought I might be overdriving Q4, so I replaced it with
a 2N5296 from my junkbox, but that just doubled the volume of the noisy
output. If anyone sees something I should but don't, please post. The
only thing I can think of is upping the voltage on C8 and C9.

Any help is *greatly* appreciated...

Dave



So if you are not able to do the basic math you can at least run the sim to
get an idea about what might have gone wrong.

petrus bitbyter