Search found 8 matches

by nibbler
Sun Feb 25, 2024 5:54 pm
Forum: Community
Topic: Constant current IR LED circuit
Replies: 26
Views: 74417

Re: Constant current IR LED circuit

ok 3 diodes and 2 Ohm: about 130mA
4 diodes and 2 Ohm: about 190mA

Maybe I should consider using a different transistor? The TIP120 is a bit too huge I guess.
by nibbler
Sun Feb 25, 2024 5:11 pm
Forum: Community
Topic: Constant current IR LED circuit
Replies: 26
Views: 74417

Re: Constant current IR LED circuit

This just makes the signal weaker, just tried with 4.5 Ohm and 2 Ohm. According to your article: "Next we look at R1/R4, which at 2.5ohms means that the current going through the resistor will be 0.5/2.5 = 0.2A or 200 mA." If I put 4 Ohm there it would be 0.5/4 = 125mA or 0.5/2 = 250mA. Fo...
by nibbler
Sun Feb 25, 2024 1:07 pm
Forum: Community
Topic: Constant current IR LED circuit
Replies: 26
Views: 74417

Re: Constant current IR LED circuit

photo.gif circuit.gif I know missing a resistor in front of the LED could kill it but the bursts are so short and for visual reasons I replaced the IR diode with a cheap yellow one. It is a bit risky, yes. Signal (IRRemote) : (6 + (16 * 3) + 1) * 526 = 55 * 526 = 28930 microseconds or 29 ms The IR ...
by nibbler
Fri Feb 23, 2024 5:51 pm
Forum: Community
Topic: Constant current IR LED circuit
Replies: 26
Views: 74417

Re: Constant current IR LED circuit

After working a looong while on other parts of this project I am back at this point, now I built myself a small ammeter to see what actually hits the LED. However the max I am getting is about 10mA. timestamp/busvoltage/shuntsvoltage/loadvoltage/mA/mW 45491327 / 0.87 / 0.97 / 0.87 / 9.90 / 10.00 The...
by nibbler
Mon Jul 25, 2022 5:29 pm
Forum: Community
Topic: Constant current IR LED circuit
Replies: 26
Views: 74417

Re: Constant current IR LED circuit

Thanks alot, I´ll alter the circuit according to that.
by nibbler
Mon Jul 25, 2022 8:36 am
Forum: Community
Topic: Constant current IR LED circuit
Replies: 26
Views: 74417

Re: Constant current IR LED circuit

Okay good to know. So as long as the power source can provide the amperage I could add even more LED?
Schematic attached...
by nibbler
Sat Jul 23, 2022 6:04 pm
Forum: Community
Topic: Constant current IR LED circuit
Replies: 26
Views: 74417

Re: Constant current IR LED circuit

I used a TIP120 as transistor, apart from that just like your circuit and a LD 274-3 IR diode.

Double the output? Couldn´t I get more power to each LED in a parallel circuit?
by nibbler
Sat Jul 23, 2022 9:50 am
Forum: Community
Topic: Constant current IR LED circuit
Replies: 26
Views: 74417

Re: Constant current IR LED circuit

Hello to AnalysIR, I rebuild your "one LED version" circuit (thanks for this work and inspiration!) but as a electronic clumsy I was wondering what the point of the R2 actually could be. I am currently driving this one with an ESP32, so available current that can be drawn is limited but at...