SCR Powerblock Tester Circuit Diagram

Click here to Subscribe:  http://goo.gl/DDfVab
https://youtu.be/YOzw9btb--k SCR Tester in Action
Diagram of a SCR Powerblock Tester I designed and built.
Designed and tested with iCircuit on an iPad.
Note: not show in the schematic but the actual tester has two amp panels for current readout.

-----------
This prototype device tests the Gate Trigger Current (IGT), Latching Current (IL) and Holding Current (IH) of Powerblock SCR Modules (Thyristors). 

The dial, led indicator and amp panel on the left are for the gate trigger and current. The dial, led indicator and amp panel on the right are for the A/K Latch and Hold Current.  
When the trigger button is pressed current must be increased with the dial until the right led lights - that is the required Gate Trigger Current displayed on the amp panel.
Now the A/K load current must be increased until the right led lights and stays on after the trigger is released. Then the SCR is latched in the On state and the current displayed on the amp panel is the required Latching Current (IL). Current can be lowered down to the Holding Current (IH) for the specific SCR under test and still stay in the On state (check data sheets). If current falls below (IH) the SCR will turn off.

This prototype was made since I couldn't find such a product on the market to test large Powerblock SCRs requiring high IGT and IL currents. 

Next project after I make the final polished version of this tool is an (IPM) Intellimod IGBT tester.