5V to 100V control with SCR

[little_carlos]

Hi, im making test to control a 100V signal (That goes to another transistor to control a Relay) with an SCR and the SCR signal is 3.3V from a microcontroller.

The problem is that the output voltage in the SCR is only 3.3V, same as the gate. The SCR acts ON and OFF as it should but the voltage is not 100V, yes, the Anode is connected to 100V (DC, since comes from batteries in series). And the output is the Cathode.

Should I be getting 100V in the cathode or im mistaken? Any suggestions?

The SCR im using is the C106B.

Im controling the SCR using a PUSH-PULL NPN-PNP config at the gate.

[IanMacdonald]

An SCR can only turn ON when powered from DC. Nothing you do to the gate can turn it off. It stays on until the power is interrupted.

SCRs do not lend themselves to 'cathode follower' arrangements, if that is what you mean.  The load is typically in the anode side.

If you need to switch the live side of the 100VDC, then you need two transistors, one to 'level shift' the control signal and the other to handle the power switching.

[capt bullshot]

The way you describe your circuit makes me think the SCR will just destroy the driver stage (or the micro or both) when it turns on. Because the gate will follow the cathode potential once it really turns on.
To use the SCR in that configuration, you should use a suitable pulse transformer to isolate the gate/cathode from the driver, so the cathode can go to 100V without harming the driving circuit.

Otherwise, a schematic or a simple sketch will help us to understand your problem and give you hints.