How this switch working?

[Yoyok]

Hi, I have found a schematics to car ign. in picture below from internet (but I forget the address, sorry). But I confuse how its work! It's seem stranger to me because this sch. doesn't follow the rule about transistor as switching. But it's working well.

I will explain how this sch is work. 1. when breaker closed the coil will store the energy. 2. when breaker open the energy release to spark plug and the engine will start and run.

Can somebody tell whats going on with this circuit? How good R value? I try to change from 10k, 1k, 100 and it's seem work well. (I'm sorry if my english is not good).

View attachment 40032

 

[indulis]

It is a flyback converter. The secondary, with the polarity as shown will go negative to the collector of the transistor. The resistor is used to turn off the transistor when the breaker opens. It value isn't critical, but you can waste a lot of power if you make it's value to low.

 

[Yoyok]

Thank for your answer Indulis! Now I will search about flyback converter to make everything clear. Thanks again!