ESP32 driving an IR LED confusion

pabl40
Posts: 16
Joined: Thu May 02, 2024 11:12 am

ESP32 driving an IR LED confusion

Postby pabl40 » Fri Jan 10, 2025 7:18 pm

I have an ESP32-C6 interfaced to a simple IR LED module below.

I simply just connect an ESP32-C6 GPIO output to the DAT input and it drives both the normal LED and IR LED well.

I'm just not sure how this is possible, mainly in the case for driving the IR LED? How there is enough current.

The ESP32-C6 GPIO output voltage is 3.3V. If i'm not mistaken, there would be a voltage drop of at least 1V across the IR LED, and therefore across the 220 resistor 2.3V, and so maximum current would be around 2.3V/ 220 = 10 mA.

It states that the IR LED needs 100 mA. Confused:)
IR_LED_MODULE.png
IR_LED_MODULE.png (92.38 KiB) Viewed 858 times

MicroController
Posts: 1954
Joined: Mon Oct 17, 2022 7:38 pm
Location: Europe, Germany

Re: ESP32 driving an IR LED confusion

Postby MicroController » Fri Jan 10, 2025 11:53 pm

An LED doesn't need a minimum current; it will happily emit photons while any electrons are flowing. In fact, the number of photons emitted, i.e. the brightness of the LED, is proportional to the current only.
If an LED is spec'd at "100mA", that's either its maximum permissible current, or its "nominal" current at which it delivers the specified brightness. Less current is always ok, just with less light output.

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