electrical nerds, transistor codes

adolf hamster

adolf hamster

adolf hamster

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Joined
18 Oct 2012
Posts
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hi guys, i'm trying to reverse engineer a circuit which has a pair of transistors on it.

unfortunately in my testing i *may* have slightly over-volted the circuit to try and get a bit more kick out of it and i suspect the magic smoke that ensued might be from the transistors even though they look fine.

the markings on the side read thusly:
N:SD
965
72215

checking continuity i'm getting no resistance between any pair of legs so i think they're fried.

any ideas? google just gives me a bunch of generic links to shops selling transistors.
 
sweet, it's part of a bug zapper that i've been using for a project, hope is if the thing it's powering works then my next job will be to make a much beefier version that can put out a lot more power, currently it's taking ages to charge up which is fine for a test.

unfortunately my electrical knowledge just about extends as far as reading/writing wiring diagrams and not understanding what on earth is happening.
 
It's got a 5 Amp collector current limit so is quite a high power capable device, often used in camera flash units, hence why you are probably using it in an HV bug zapper, I'd just get the same part numbers off Ebay rather than trying to match it. More info here:

https://alltransistors.com/transistor.php?transistor=20310

Don't test it by sticking your tongue in it, it'll probably make you jump a bit ;)

If it doesn't work I have a nice little single phase transformer here that would make an effective bug zapper. 6600V at at least an Amp :) You can zap your enemies as well then...

http://www.chriswilson.tv/transformers/transformers.html
 
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so if i'm reading this right, my circuit has the collector and base going into a transformer (which seems to have fried wiring so i can't measure the contacts properly)

the connection seems to be emitter to ground, base and collector going into the coil. i think the coil is blown but it seems to be:
collector goes to +ve through 1.6 ohms of coil
base goes to +ve through 1.6 ohms of coil and a 2.2k resistor
the 2 coils are going to seperate pin pairs but they're the same resistance.

so if it fried then it must be the emitter-base voltage was too high as that's only 7v? i was running it at 12v so seems likely (although i don't know what the induction in the coil is doing)
 
Chris Wilson said:
I doubt the bases would go to the coil, has it run correctly previously? I am no electronics expert mind...Just a hobbyist.
Click to expand...

the bug zapper was a cheapy tennis raquet type one from amazon, so it came pre-assembled.

i'm using it as a high voltage generator for what i suppose technically qualifies as a gauss gun, the idea was to hook it up to a larger capacitor bank that i have already and use it to charge them up and see how the coil behaves.

unfortunately whilst it'd do around 900v stock, when i removed the stock capacitor and replaced it with a connection to my capacitor bank it would only charge it up to 93v using it's default 2x aa's, unfortunately using a 12v battery to boost it a bit (go big or go home :p ) killed it

the thing's just a proof of concept at the minute, find out how much power this coil needs to fire (if it fires at all), if the coil idea works as intended then i'll need to build something that can take a 11.1v lipo and do the same thing but much faster (5 minute charge times are ok for a test rig but not for the final product)

i've got another one coming, so i'll take the diagram of the transformer down before i blow it up for reference
 
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