Unijunction Transistor SCR Photo Flash Control Circuit

Using an SCR to turn on a HV photoflash strobe.
Understanding Unijunction Transistors Theory Operation
www.bristolwatch.com/ele4/uni...
Unijunction Transistor SCR Photo Flash Control Circuit
www.bristolwatch.com/ele4/fla...

[@mikebond6328]

I like the way you show the actual circuit AND the schematic. Makes the overall circuit easier to understand. Thank you.

[@jp040759]

Love the way you repurpose stuff. Hopefully newbies take note of this fact in your videos. Good use of what appears to be a motor capacitor. I have always thought about using a TRIAC as an SCR. Never did it since I have SCRs of various sizes handy. Love them there xenon strobe circuits!!!!!!

[@julianmiles6604]

The step up transformer is being driven push-pull so the rectifier should be a a full bridge in order to balance the magnetic flux in the transformer.

[@LewisLoflin]

This s demo and the output is high frequency. It works as is and works well.

[@dalenassar9152]

Hi Lewis,
I have tried circuits somewhat like this, but my SCR latches on after the first shot, even with less 'holding current' than you are using here (looks like about 330v through 100k=3mA)...BIG problem for me since I need a 70-80Hz rate. Any ideas? what do you think about MOSFETS?
THANKS AGAIN
Dale

[@LewisLoflin]

Are you AC or pulsating DC? Pure DC will not work.