Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Att.. Skelle. This is where the components are, the resistors are deposited & trimed on a Ceramic sudstrate. To measure them you will need to remove the transistors. Also the capacitor will need to be removed carefully to measure This is a Red module.
Here we go. Strangely enough R1 and R3 are not same value, but maybe that's due to tolerance in PCB resistors? Which resistor are to be high wattage (2 Watt)?
Hope this makes sense to you Debe.
Defenitely no capacitor present.
R1, 1.2K is the 2W resistor. Just wired up the circuit using your values & it works on my test rig. Good spark. On your engine if the Q1 fails you will have to ad a Transorb to protect it. But try it out first.
Brilliant. How can i check the polarity of Q1.... I'm thinking plus/minus, and grunding/not grounding.
Would think there's an equvivalent PNP/NPN to the 2SD1071.
Does the text on my Q1 Sound familiar?....if it does then no problems.
Can see you pencilled in 1,1K? really? Dont you think 1,2K would work?
OMG....lot of questions..sorry
I think i'm just isolate the prototype, and let a red and black wire come out...then easy to shift the polarity, even for someone with no electric skills. Currently using the Pink Atom on 2 Velo Solex from 1967 and 1968......and it really works good. On top....if you can find the Pink module, they charge 35$....uhhhh for 3$ parts
I would stick with a 2SD1071 as it has good high voltage rating & it is an Ignition transistor. This is how I construct the modules, they do need a heat sink. After testing that they do work after construction, I use 5min Araldite to seal them from vibration.
I'm going to try out these SMD/SMT resistors, and draw a tiny PCB, just to see if i can remember how.
I'm Radio/TV / Electronic Engineer from early 70's, so a lot changed over time.
I can't find a 1,2K 2watt, so testing this type in 1watt... They should be better to get rid out heat...but we will see
This is my test circuit & the actual values that I used. This is also what i test Ign modules on. It seems to work quite well. Another transistor that does work in these circuits is ST901T. Not all ignition transistors work. Interesting to see how you go using a printed circuit board & SMD components. ( I used to repair electronics TV & VCRs from 1975 to 2010)
For got to answer your polarity question. With Atom modules if you don't get a good spark or none , then reverse the polarity conections. It all depends on the polarity of the pulse from the ignition coil. They can be either a positive or a negative triggering pulse.
Hi again Debe.
This R1 , 2watt resistor.....how much effect are really loaded into it? Would you be able to measure the voltage loss across the R1 in your test setup? I haven't got all parts i ordered, and i can't find a SMD over 1 watt.. Mr Ohm said.... U : R (1,2k) = I , and P = U x I.... Please...?
I would think you will get away with a 1W resistor. The only way i could measure the voltage was with a CRO as its pulses we are measuring. The C/B is across the resistor ( I had used a 1W resistor). The other picture is B/E the drive pulse. The voltages will vary from Coil to Coil. This coil has a total of around 97V PP.