Seems to me the "ignition tester" in the thread subject shifted to "ignition circuit"

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There may be some problems putting 120 volts into a 12volt input winding.

You start low. You are not putting 120 VAC into a 12 V coil. Still have no clue where that dimmer went to, then too my organizational skill have gone downhill. The merit to the dimmer is the sharp cutoff of the waveform.

Ron

 

Seems to me the "ignition tester" in the thread subject shifted to "ignition circuit"

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This can only test if the coil is good/bad nothing else.
*circuit diagram for ignition tester.

 

If the situation is an engine not starting, then a "good/bad" check could be useful, except if the result is "bad", because such a simple tester will probably not provide the "WHY" information. BUT it will tell me that the fault is not a lack of fuel or compression.

 

What is it between pin 4 and +12V a diode or LED?
If its diode what type?
Also the diode between pin 6 and 7.

They are common type 1A 400V diodes. Also the 12V power is for vehicle ign systems. Small engine coils use 8V.

 

These testers are & can only show that a coil is either not giving a spark or weak yellow spark. What you are looking for is a good sharp snappy blue spark, any thing else is either not going to ignite the fuel or not properly. The why information on most small engines is inmaterial these days, as the ignition systems dont use points. The coils are eitherCDI or Transistor trigered with an internaly epoxied circuit. so if they fail a test then they are just throw away.

 

There are still quite a few "antique" engines around, though. OLD cars, as a common example: collectors items.

 

Added diode D1, misses in model of BU931 transistor:

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I have build the circuit, but it sparks only when i turn on/off the circuit from the 12v.

 

I have build the circuit, but it sparks only when i turn on/off the circuit from the 12v.

Check 555 timer, on circuit it is shown in bottom view.

ADDED:
Show us schematic, you experiment with.

 

QUESTION: HOW MANY moped ignition coils does the TS want to test??

 

QUESTION: HOW MANY moped ignition coils does the TS want to test??

i have ~20 ign. coils for testing. + i need it for testing when a moped comes for repair.

 

Oh Wow!! Now the need is clear. One note of concern! Adding that diode to protect the switch contacts will certainly also affect the performance of the coil a fair amount, since it damps the ringing. But it seems to me that the resistance test is still needed, although certainly the spark test is the final check.