I'm trying to fix this CDI off a motorbike for a friend, but I can't identify this component, any help would be very much appreciated.
Sorry about the scratch I had to dig it out of resin.
Can somebody tell me how it triggers without a trigger coil?
Thanks
Nide1
Thanks for the reply perieanuo, I thought it must be SCR.
Can anybody tell me how to work out gate current/voltage in simple layman's terms.
Thanks, Nide1.
gate voltage here is irrelevant, gate current is given i guess by the ignition coil vie 1u5 cap, rectifier diode and 86ohm//diode and 1k resistor, and the zener limits the peak
i didn't do any calculations, but there are 'normal' gate current scr's and more senzitive ones, i think a normal one will do the trick, like i pointed before
see
https://uk.farnell.com/c/semiconductors-discretes/thyristors/thyristors-scrsthe normal ones are like 8-10mA senzitivity on gate, either you use a 'normal' either a <1mA one, but my bet is it's a regular one, in that environement a sensitive gate is not desired if you design such a thing, automotive is noisy and threshholds are generous
Thanks again perieanuo, I'll get a 2N6509G and give it a go, I've tested everything else in the circuit so we should see a spark.
To buy one which comes with stator plate will cost a 100 to 200 pounds and he said he always liked how the engine ran, so worth doing.
Thanks again.
Nide1.
ok, just please keep us informed
Hi,
I fitted SCR(BT151-500R) and it worked like a dream, the best spark he had ever seen.
So thanks again perieanuo.
He's got to sort the carb/fuel out, but I've done my bit.
Thanks
Nide1
you're welcome, glad to hear it works, you can now press thanks to my post
best regards, pierre
I thought I put a picture of the bike.