Hi,
Negative resistance region occurs when current through device decreases if voltage across it is increased.
Looks like such region is absent in SCR. If it is not please describe how it occurs.
Thanx.

 

When you build SCR from discrete devices (BJTs) this device will have a negative resistance region. But in this case, we called it the Programmable Unijunction Transistor. And maybe SCR are "specially designed "to do not have "large" negative resistance region.

 

When you build SCR from discrete devices (BJTs) this device will have a negative resistance region. But in this case, we called it the Programmable Unijunction Transistor. And maybe SCR are "specially designed "to do not have "large" negative resistance region.

PUT.....blast from the past! I haven't seen one of them in ages; who still manufactures them>?

 

Places like: https://www.centralsemi.com/content/product/

 

Places like: https://www.centralsemi.com/content/product/

Very cool!
I see a HUGE "cottage industry" for diminished support devices. As an RF engineer, I find it even difficult to find good RF power transistors. CentralSemi will definitely have my business.

 

Yes SCR do show a negative resistance region, but it is only a trace and it is an uncontrollable region where we can't find the Q point hence we do not have a region of operation there so the region is of no use. that is the only reason why SCR is a passive element.

 

It looks like a negative impedance but that only occurs at the breakdown voltage point where the SCR is not normally used.