🚀 go-pugleaf

I've received several requests for info on the circuit I'm using to ring a
telephone.

To all who are interested:

1) Please realize it's far from perfect.

2) Give me some time to respond in depth - I must finish the project and
present it this Monday.  (Aaaargh!)


Basic Description:

Using a transistor was a big step for me.  I'm an analog virgin.  I'm quite
comfortable with digital, though.  ...soo...I didn't use nifto keen RC
circuits and coils and transformers (o.k. one is the other) to do the job.

Instead, I use a 555 to drive two optoisolators (anode of one, cathode of
other).  These switch two NPN power transistors which are being fed ~35VDC
each (with a common ground).  I used a transformer to supply 60VAC center
tapped (one half for each transistor) and filtered the power through a
full wave rectifier and capacitor (one set for each side).

~50VAC (seems to change every time I measure it) @ ~22Hz (I just kept plugging
in resistors.) comes out.

I'm betting that many of you are slapping your heads, thinking "Geez!  Why
didn't he just use a PDQXYZ5 circuit!!??"  (about the same thing I feel when
I see people who just keep typing in the same series of commands instead of
using batch files/scripts...)  Again, this was the solution I came up with
and it works (for some phones).  Success!!!

I'll post more detail when I'm caught up a bit more.  (HA!)

--kyler