[Need help with SCR (Silicon Controlled Rectifier)]

Hello electronics gurus of the CPF world! A LOOOOOONG time ago (in fact, I was about 15 years old), I first learned about SCR’s… Silicon Controlled Rectifiers, if memory serves. As I recall, they could be used sort of like a solid state relay, plus could be made to latch in the “on” state. In other words, I could connect one inline with a circuit, and it would act like an open switch until a momentary current was applied to its “gate” (my word, not necessarily the technical name of it), at which point the SCR became like a “closed” switch. Now here’s the interesting part: once in the “closed” state it didn’t matter if the current on the gate was removed, the SCR would remain “closed.” I read a lot of examples of Silicon Controlled Rectifiers circuits, but I am still confused.

Am I describing this part accurately, or do I have it confused with something else? I know such a component exists, but am hoping someone could explain it to me.

I’d also like to understand some basic properties for such a part…

Does it drop a voltage across it like a diode does?

Does a small amount of current “leak” even when in the “open” state?

Will it truly remain “closed” forever once tripped, so it could keep running a load for hours, days, weeks, or even months… or would it eventually “open” itself again?

Is there a significant heat buildup through this part?

Thanks in advance to whoever helps me understand all this! I appreciate your patience in dealing with such a dim electrical engineering wannabe as me. /ubbthreads/images/graemlins/blush.gif

[How to use 74HC595 Shift Register with Arduino?]

The following  attachment image shows the circuit diagram of interfacing 74HC595 Shift Register with Arduino UNO.

Could you please tell me what is the principle in this Circuit Diagram?

Here  is 74HC595 Datasheet.

[Interesting Project Sharing]

Hey guys, saw an interesting project using ATtiny13  to make a infrared remote control, just thinking maybe someone might be interested.

link:https://www.youtube.com/watch?v=r57NqAyuhvY