Hello there.
Im just starting to pick up electronics as a hobby again. I did some as teenager but never got far, Im heavy into computers, low level programming, linux, etc, but got interested in raspberry pi and arduino lately. I started with a raspberry pi 2 and in the same order chucked in an arduino uno because they were so damn cheap. Then bought a 37 sensor kit, and now recently got another order delivered with a rbpi3, an (second) arduino uno, two arduino nano (v3), sd card readers, gsm module, 8x8 led matrix, etc.
My new favorite is the arduino nanos, so much versatility in such a cute little package. Unfortunatly I quickly messed up and short circuited one (shorted the ICSP vcc-gnd pins). That was a sad moment not because of money loss but because getting new ones from china takes so damn long. Yes Im cheapo ordering from Aliexpress.
Anyways this got me interested in this current limiter circuit which I think could save me from some future losses. Im especially worried about burning power supplies because my next expected shipment contains two 5V 5F supercaps. At first I was trying to understand the article on wikipedia (
https://en.wikipedia.org/wiki/Current_limiting) but didnt have much luck since I still dont have components to experiment with. So I found the evaluation copy of Multisim which allowed me to come up with this circuit that seems to work.
The conditions for the circuit above is;
C1 is a small placeholder for the supercap,
R4 is a placeholder load for a 32x8 (4x 8x8) LED matrix (or up to 6 of them), I measured a single element to draw ~60mA with "normal text" scrolling on it.
R5 is shorted out (zero ohms) to test the circuit. At 100 ohms this circuit passes about 110 mA through U1.
Now I would be grateful if someone with more insight and experience than me could comment on this circuit. About how safe, efficient, reliable, etc, that this circuit is or could be? Could it be improved?
Id like to add an indicator LED to light up for overcurrent/short circuit warning but Im still too dumb to figure out where and how to place it without breaking this circuit completely.
/A