ESP8266 Community Forum

- Wed Nov 23, 2016 8:58 am #58562 Hello,

I need a little help, I used the diagram to manage an infrared led with a spare 8266.
The power supply of the circuit is made with a transformer 4.5v 300 mA and a card to power the esp (http://www.ebay.fr/itm/Module-dAlimenta ... SwY0lXTBxI), the transistor is a pnp 2N3906 as on the diagram and the led is a 5mm TSUS5402 5V 150mA 950NM 22 °.
My problem is as soon as I plug in my 5v- 3.3v power supply heats up enormously and the led too; If I plug on a battery 18650 no worries.
I tried to power the led in 3.3 v same.
A charitable soul can help me


thank you

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Last edited by doubleve on Wed Nov 23, 2016 10:54 am, edited 1 time in total.

- Wed Nov 23, 2016 9:36 am #58564 You should never drive a LED directly from a voltage source without using a resistor in series. It works with the battery probably because its internal resistor is limiting the current, but the power supply can provide a higher current, and hence the heat.

- Wed Nov 23, 2016 10:54 am #58568 I followed the board I put a resistance of 100 ohms the led does not heat any more and the card 5 v is slightly hot. I will test like this
thank you