Basic thyristor questions TYN1225

Question

I have the component TYN1225 that I believe to be a thyristor.

I just read about thyristors that are described as rectifiers enabled or non enabled on demand.

According to what I read and understood the thyristor conducts in only one direction and its conduction may be enabled by activation of the gate.

So the thyristor when not activated is non-conductive in both directions, while if activated conducts in one direction only from anode to cathode.

I took the component I have and it behaves as follows (tested two of them to be sure):

When a positive voltage is applied to the gate relative to the cathode then the component conducts in both directions. When conduction is from anode to cathode the component conducts even if the voltage to the gate is taken off. When conducting from cathode to anode the component conducts only during the time that the voltage is applied to the gate.

So I would like to know is TYN1225 a thyristor, and if yes, how exactly do thyristors behave?

I realized later on that in my experiment, I didn't connect a resistor between the source of voltage and the gate at first. So it seems that in that case the gate is somehow "overcharged" and the thyristor conducts also in the reverse direction. When I added a resistor between voltage source and gate the "normal" behavior showed up: blocking in one direction and conducting in the other.

Anyway, a complete explanation would be nice to have.

Answer 1

For testing SCR, one could use something like this.

• On resistive only Load.

We need a synchronized pulse (with sine wave), "delay" and "TPulse" adjustable.
We can see then, that where the SCR is fired, it turns ON (sine positive voltage), and turn off on the negative part of the sine (pulse does not matter).