Hockey Puck SCR

I received a Hockey Puck SCR part # VS-ST230C12C0GI-ND.
When I Measured the Continuity between the Cathode and the Gate, it is a dead short, “Buzzes”
Is this Normal for a uninstalled Part…? Does the part need to be clamped down in the installation for it to not Buzz between the Cathode and the Gate…? Or is the part Bad…?

My 10A TO220 SCR parts do not Buzz between the Cathode and the Gate.


Did you have the power hooked up? The power needs to be off when testing continuity. so I not sure why you have a buzzing.

Hi @rs.acme.gis

You may be biasing the internal diode. What number is reading on your meter when you are measuring continuity? You could try measuring across it with the meter in lowest resistance setting and see if that renders any values.

This one is right out of the package never been installed, dead short between the Cathode and the Gate…

Ryan, 014 on my meter in diode / continuity test setting, in both directions.

Ryan, in the 200 ohm setting, it is reading 14.9 ohms in both directions

Try doing a resistance (ohms) reading with positive lead on Anode, negative lead on Kathode.

Should get high resistance. Then put Positive lead on Kathode, Negative Lead on Anode. Also should get high resistance.

Then connect positive lead to Anode and Gate, and negative lead on kathode, should get continuity.

Your meter is inducing voltage into the circuit through the positive lead, turning the Gate on.

Ok, it has High resistance between the Cathode and the Anode in both directions. Also High resistance between between the Anode and the Gate in both directions.

now connect positive lead to both Anode and Gate and Negative Lead on Kathode.

You should get continuity when doing this.

That Buzzes with 014 on the meter.

As it should. The way your meter tests the circuit is injecting voltage. You’re turning the Gate on with your leads.

Ok, so you think this is a good part…? Will clamping it down in the instillation change this behavior?
It is a spring loaded part, and Clamping it between 2 heat sinks with x amount of torque, is the installation.

Based on your test I don’t see any indication the part is bad. Clamping it down shouldn’t change the behavior.

1 Like

Just make sure the Anode/Cathode polarities are correct when clamping it down

The previous part with the same Part#, would show 11V on the gate when when installed, I thought I Had blown it up somehow… The very first part 238-N0465WN140-ND never showed 11V on the gate when installed. Unfortunately I killed it…

No problem with that…

1 Like

Hi rs.acme.gis,

I guess what you are seeing is normal. The Thyristor is a 410A device, so expect to have quite a low resistance at the Gate. It needs 1.8V and 90mA at the gate to turn on. On datasheet page6 you can see from the curve in Fig. 11 that, for example, at 0.25Vgk the current Igk is 10mA, i.e. the resistance is 25 ohms.

However, the spec does not mention about the reverse gate biasing, thus cannot say if it is OK that the readings are same with both polarities (would imagine that there is a reverse protecting diode between gate and kathode, in which case it would explain the readings).

heke, AsamaLab