Re: Alarm system transformer + power supply (would both go bad at once?)

[Danny D'Amico <danny@xxxxxxxxxx>]

On Mon, 25 Nov 2013 20:07:16 -0700, Tony Hwang wrote:

> What if the new board blows up when replaced?

That's why I only want to spend the $104 to replace it.
It *does* have overload circuit protection besides.

> Are you planning to protect it some how from that occurring?

I've done plenty of smoke tests in my life.
This will be one of them.

> BTW, looking at arrow marking on diode
> can yu tell which direction current electron or current flows?
> Can you tell which lead is the cathode or anode?

Heh heh ... here is a board I built many years ago to test
impedence (j omega stuff). I wired a diode to house current!
You'll notice the diodes.  Particularly, you'll notice that the
nichrome wire resistor has the same impedance as the the capacitor.
(I couldn't find an inductor of a large enough size.)
 FRONT: http://farm6.staticflickr.com/5491/11061412564_d241b67f1e_o.gif
 BACK: http://farm4.staticflickr.com/3800/11061387306_4b928f65c1_o.gif

Also notice this circuit, where I used 555 timers (I think that's what
I used), way back in the 80's, to measure capacitance and resistance
simply by counting the flash rate ...
 FRONT: http://farm8.staticflickr.com/7362/11061411704_cf3e84efa3_o.gif
 BACK: http://farm3.staticflickr.com/2893/11061410864_5dfa50a070_o.gif

I did those circuits in the early 80's but, of course I know
about the shape of the diode curve and which is the anode and
which is the cathode.
 http://sub.allaboutcircuits.com/images/03256.png

Everyone knows this basic stuff... even we accountants.