Originally Posted by Exerpt from YDNA Email
Well, components have yet to arrive....but I've been dinking around with
the boards a little more. I'm now less concerned with the voltage
amounts and more with the current...although I'm virtually sure the
problem is indeed with the Chaos transistor. My current thought (har
har) is that the Chaos transistor is too small to provide enough
current, and upwardsly enough power. It's physically pretty small which
doesn't usually make any difference, but I wouldn't be surprised if that
were the case here.
One of the reasons I think this is because the board seems to operate
the other low-power solenoids decently. It doesn't seem to have any
trouble until I hook up a large resistance coil, such as some 4.2 watt
MAC solenoids I have here, a large Parker solenoid for industrial use,
etc. The Chaos doesn't seem to have much trouble with many
indirect-acting solenoids, only these big direct acting ones.
There's also this odd issue of the Chaos transistor leaking power to
through the circuit while it's idle/off. All transistors leak a small
amount, just like how all capacitors leak some energy, but in this case
I was able to measure the amount of power passing through as being
almost 0.4 volts. I'm not an expert on these things bit it's weird to
see a 0.4 spike pop up every 2 milliseconds then go back down to
0...repeat over and over. It's possible to be some kind of feedback
being produced by my scope, but I don't think so....hmmm
Anyway, the components I chose are very large and will hopefully provide
enough juice to be useful. I found a startlingly huge transistor which I
hope will function okay, but I admit I'm weary since it's made for audio
applications and might not work as good unless there's a whole circuit
built for it. We'll see....the fallback transistor I selected is rated
to 50 volts at 2.4 amps, and my diode is good to similar amounts,
although I'm trying to find a bigger one just in case. For reference the
Morlock's transistors are 30 volts at 4.6 amps, which is certainly large
enough to power anything used in a patinball marker...hopefully some of
that is overkill.
The ***** of it is even though these components are tenfold what we need
on paper, in reality it'll be a different situation. I'm sure the Chaos
transistor is "rated" to more than these solenoids require, too. Just
with a smaller gap between the solenoid requirement and the transistor
rating.
Enough of that. I'll let you know when something more exciting starts...