thyristor firing timing

[xjackal]

thyristor firing circuit

hi friends.i have a simple design problem.i want to trigger thyristor while the circuit produces full wave.so u know that circuit and the timing should be the same with them.help please

 

[artem]

thyristor firing

do you mean for both semiperiods of sine?
If so, use one triac or 2 thyristors connected in parallel but opposite polarity or thyristor connected in diode bridge :

https://www.littelfuse.com/data/en/Application_Notes/AN1009.pdf
https://www.littelfuse.com/data/en/Application_Notes/AN1003.pdf
https://www.littelfuse.com/data/en/Application_Notes/AN1007.pdf

 

[xjackal]

firing circuit of thyristor

thank u for the reply.but my circuit should be like this.i know i can do it with resistors and cap but how and how can i fire up the thyrstor at their right time for their turn?

 

[IanP]

thyristor firing circuits

The easiest way of synchronized firing of both thyristors is through pulse transformer(s) ..
Have a look at Fig.B or Fig.E .. see picture below .. configuration --> CT (centre tap) ..

Regards,
IanP

 

[xjackal]

firing circuit of thyristor,pdf

so i should use pulse transformer instead of the transformer.and how to trigger them.can u post a clear image IanP.and i should have 220v,i mean 110v for one part,110 for the other.
how can i provide it.
or is it the scheme that u send before taking ac from primer and rectifying it with bridge and pulsing it to thyrstors?
but what should be the voltage of the pulse transformators this way?
thnx for the help

 

[IanP]

thyristors pdf

You can leave the concept with a transformer in CT configuration and two SCR used as controlled rectifiers .. I don't know your application in details, but having an isolation from the mains is always a good idea ..

Take a look at the circuit below ..
It shows an example on how to controll SCRs with a pulse transformer ..
To start with, you will need a reference pulse at "zero-crossing" - 2-transistor circuit fed directly from 100Hz signal from the r-bridge ..
If you don't want to use firing angle control you can remove both 555 timers from the circuit and directly connect collector of the zero-crossing detector with the gate of the MOSFET on the primary winding of the pulse transformer ..

More details on this circuit can be found at:
http://www.scopeboy.com/tesla/ol2psu.html

Regards,
IanP