I don't know the difference between a pnp and an npn, but I had a 
transistor.  All I knew was the middle terminal acted like a valve for 
current to pass between the outer terminals.  So how did I find out?  I used 
a pot to find breakdown, replaced it with an equivalent resistor, and went 
from there.  All I know from there is when the base was grounded, it opened 
the valve, and I had my circuit.

Later I was working with a reed relay.  Apparently the coil was polarity 
sensitive, so I figured that one out and I had my circuit.  That doesn't 
count all the time I spent trying to use a transistor.  This time it failed. 
The voltage on the radio speaker wasn't enough.

So now I have two clocks, one with a fire alarm bell and the other with a 
fire alarm buzzer pending shipment.  When it gets here I can just 
conveniently plug it in to the extension cord female dangling off the back 
of the clock.

If there's a mistake that can be made, I will routinely make it.

Mistake Crusader Jon from Ohio 

On Tue, 2 Mar 2010 00:05:01 -0500, "Jon" <j...@peoplepc.com> wrote:

>I don't know the difference between a pnp and an npn, but I had a 
>transistor.  All I knew was the middle terminal acted like a valve for 
>current to pass between the outer terminals.  So how did I find out?  I used 
>a pot to find breakdown, replaced it with an equivalent resistor, and went 
>from there.  All I know from there is when the base was grounded, it opened 
>the valve, and I had my circuit.
>
>Later I was working with a reed relay.  Apparently the coil was polarity 
>sensitive, so I figured that one out and I had my circuit.  That doesn't 
>count all the time I spent trying to use a transistor.  This time it failed. 
>The voltage on the radio speaker wasn't enough.
>
>So now I have two clocks, one with a fire alarm bell and the other with a 
>fire alarm buzzer pending shipment.  When it gets here I can just 
>conveniently plug it in to the extension cord female dangling off the back 
>of the clock.
>
>If there's a mistake that can be made, I will routinely make it.

---
Murphy's Law, but sometimes it's a blessing:

http://en.wikipedia.org/wiki/Buttered_cat_paradox

JF