Unfortunately you wont find these vibrators any where, they are also 6V.

 

The other alternative is a DPDT 6V relay, one set of contacts for self oscillating with an electrolytic across the coil to give aprox 200Hz. The other contacts do the switching. This does work but still uses contacts that will eventualy burn.

 

Finaly have a circuit that actualy works. Needs a bit of fine tuning as above 3 to 3.5 Amps current draw the BD650 darlington transistor gets a bit warm. So i will need to find one that can handle more current. This will take awhile as anything you order takes more than a week to get here (nearest shops that stock components is a 3.5Hr drive one way) MrSalts you was verry close, didnt work untill added the 10K resistor. Thanks for all the help from you people, theres always different aproaches to a problem.

 

Needs a bit of fine tuning as above 3 to 3.5 Amps current draw the BD650 darlington transistor gets a bit warm. So i will need to find one that can handle more current.

You may also need one that is rated at more than 100V.

Edit: You might consider a non-Darlington such as this, since it will have a lower voltage drop and power dissipation.

 

You are right but these transistors are the best i have at the moment in PNP. Happy it does prove the concept is achievable.

 

Seem my edit of post #24.

 

Thats a NPN needs to be PNP.

 

Thats a NPN needs to be PNP.

Yes, my mistake.
I was searching for PNP devices, and didn't notice that it came up with an NPN.
Unfortunately I didn't have any luck finding a high-current, high-voltage PNP.
Back to square one.

 

MJE5852 ТО-220-3 (400 V)
Price US $3.00
https://www.transistormosfet.com/transistor?search=MJE5852
or https://www.ebay.com/itm/401706327794 (US $5.12)

 

.... or use a P-channel MOSFET instead of the PNP ?

 

If you can find an old Sony 5.1 channel receiver with a claimed 100W per channel, they use some crappy NPN and PNP darlingtons on the push-pull outputs. You may be able to use those if getting to a local shop is a challenge.

Otherwise...

https://www.taydaelectronics.com/t-...p36c-tip36-power-transistor-pnp-25a-100v.html

Tayda offers surprisingly affordable (and fast) shipping rates - I think they have a local re-distribution terminal in Denver (USA) and Melbourne (Australia).

 

Gas stoves/cooktops emit a burst of igniting sparks when the knob is pressed. Available at appliance parts stores in many flavors. No vibrator, no circuitries, simple self contained and low cost.



There is single spark types too by piezo button.

 

Gas stoves/cooktops emit a burst of igniting sparks when the knob is pressed. Available at appliance parts stores in many flavors. No vibrator, no circuitries, simple self contained and low cost.

View attachment 287886

There is single spark types too by piezo button.

And how should that be controlled for an ignition tester? Not a spark-plug tester, but an ignition tester.

 

Gas stoves/cooktops emit a burst of igniting sparks when the knob is pressed

The purpose of the tester is to test ignition coils, not generate a spark.

 

This is the tester for engine ignition systems. Project is on hold till i get MJE5852 transistor & willtry IRFP9240 MOSFET P type. One lot has to come from England & the other from China to get at a resonable price.

 

Still waiting for higher voltage transistors. But this circuit at this stage works as a replacement for the vibrator in a Merc o tronic tester. It works fine on small engine magneto ign coils at around 1.5A current draw. But the transistor gets quite warm when testing car ignition coils on 12V at around 2Amps. Can i just paralell a second transistor as in circuit to handle the extra current?

 

Should be ok.
From the datasheet it looks like you may need to clamp the collector voltage to 100V to prevent transistor breakdown.

 

I do have 91V 5W Zenner diodes, will fit one across the C & E of the BD650.

 

But the transistor gets quite warm when testing car ignition coils on 12V at around 2Amps.

What's "quite warm"?
Is it mounted on a heat-sink?
Will it burn your finger?
If not it may be okay.
How long does it need to be on for your testing?

 

Power, dissipated by transistor is about 4W @7V and about 12W @12V.