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WHAT is it? What is the value?


Well-Known Member
Thread starter #1
First item, I looked up the number online 3 different places show me photos of ICs. This is not an IC. It might be a 40 year old SCR. Wonder what the value is? Wonder if I can use it as a power diode? I need 100 amps for my next project. Can an SCR be used as a diode

The next item may be an SCR too it has 2 terminals on the side and comes with a very large 25 lb aluminum heat sink. Judging by the 800 amp wire that was connected to this equipment before it was scrapped this item may be 800 amp with a voltage rating of 600 volts or higher. I have 3 of these. I can not find any information online.

I hope this item is 100 amp. I can not find any information on it.

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Well-Known Member
Thread starter #3
WHO sells heat sinks? I need 1500w heat sinks.

WHAT is gate voltage? What size resistor do I need from gate to B+?

All my SCRs are the same. They are all NPN-P. Online says, gate connects to anode to keep SCRs on all the time. To make construction easy I need 2 diodes on each heat sink. To do that with mounting lugs diodes in need 2 NPN and 2 PNP. If I use 4 NPN-P SCRs I need 4 heat sinks. Wire size looks like it can handle 75 amps.

Maybe this thread is in the wrong place? Maybe it should be in Projects?
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Active Member
71RC120A ;
110A 1200V SCR made by Intl. Rectifier

T198N 600TOC;
Thyristor/SCR 198Amp, 600V made by AEG/Telefunken

Old Union Carbide house number. Generic; 300A 250v (reverse case) stud mount rectifier made by Intl. Rectifier


Well-Known Member
Thread starter #5
I tested the SCRs today 2 out of 6 are good. I put 11 VDC on the SCR then used AAA batteries on the gate. 2 batteries will not trigger the gate because it is rated 3V but 3 batteries will trigger the gate. Once the SCR is on remove batteries will not turn it off but removing 11v power it turns off. Works exactly like it should. The other 4 SCRs are bad, 1 is shorted in both directions the other 3 will not turn on.

I tested all 16 of my 300 amp diodes they are all good. My only choice is to use the 300a 1200v diodes on my 20v 75a circuit. These diodes will be bullet proof in this circuit.
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Well-Known Member
Yes, you can use a triggered SCR as a diode.

But be aware, the forward voltage will be higher, so it will dissipate more heat than a regular diode would while conducting the same current.

If that means a significantly larger heat sink, then you may be better off just buying the right diode.

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