How to test SCR/thyristor?

Hi

I am currently carrying out a damage on battery charger and stumbled on problem as it would not operate. I suspected it was a thyristor and I have no idea how to test it. Two thyristors are in the thyristor bridge circuit configuration with two subbers cicuit fitted across the thyristor respectively. I took the subber out of way and I was not entirely sure how to test it with DMM? Is there any different mehtod of test the SCR module? I look forward to hear from you intelligent guys

Regards

MM

A method I've used is:
Ohms range on the DMM
+ lead to the SCR's anode
- lead to the SCR's cathode
Should read infinite if good
Short the gate to the anode
Should read low resistance if good
With smaller SCRs the low reading should remain after the short is removed.
With large SCRs the reading may go back to infinite after the short is removed, because the DMM current is below the SCR's minimum hold current.

Ken

Is there any way to check Triacs which are basically two scr's connected Cathode to Cathode?

Same way as the SCR...almost:
+ lead to the triac's anode-2
- lead to the triac's anode-1
Should read infinite if good
Short the gate to the anode-2
Should read low resistance if good
- lead to the triac's anode-2
+ lead to the triac's anode-1
Should read infinite if good
Short the gate to the anode-2
Should read low resistance if good

Ken

please, how can i learn effectively how to use TRIAC and THYRISTOR. I have good and practical understanding of bipolar transistors and MOSFET. Any good link or tutorial will be highly appreciated as i intend to use triac with microcontroller to switch 220vac to 240vac to a pump motor without using relays. Can it be achieved?. Finally, what is the difference between SCR and Thyristor and Triac. thanks

SCRs and triacs are both thyristors.

You might want to start here:
http://www.allaboutcircuits.com/vol_3/chpt_7/index.html

For interfacing microcontrollers with triacs:
http://www.st.com/stonline/products/...re/an/1863.pdf

Ken

i will check the links and post any doubt here. Thanks for the reply.