Eagles 5pcs 1 Channel 3V Relay Module with Optocoupler for ESP8266 Module,3v Logic Level Boards,Raspberry Pi 3.3v Application

Received these on a same-day Amazon delivery, and tested them using an Adafruit Feather ESP32, which can be powered through its micro-USB plug, or an attached Li-Poly battery. The relay clicked very robustly with either power source, so it gets 5 stars from me.As is typical with this kind of product, zero documentation, and the website printed on the bottom of the board was invalid. But it was easy enough to figure out: connect GND to GND, VCC to 3.3v on controller, and IN to control pin on controller. There are two jumper pins installed on the board, and if you leave them in place, the relay coil gets its power from the controller, but you lose controller opto-isolation from the controlled voltage on the relay, which could be up to 250v AC. To gain the opto-isolation, remove the jumpers and power the relay coil from a separate 3.3v source, using the exposed connector pins nearest the blue relay (unmarked, but polarity is important). I chose to leave the jumpers in place, as I have done with similar products in the past, with no bad consequences.As always with relay products like this, if you're switching high voltages, be very careful handling this device. The terminal block screws, in particular, are at full controlled voltages. Turn off all power off before making changes.

I don't remember exactly how much since I didn't write it down, but this draws several 10s of mA while switched on. It works well enough for short bursts or for anything powered from a wall outlet, but I cannot recommend it for use with battery-powered projects. Also since this is a mechanical relay it cannot be switched often or you will ruin it quickly. If you need something that switches on and off often and consumes little power, try something like a logic-level NPN MOSFET.

Happy with this product. I use it to turn on a light using an ESP 8266. The relay so far it works flawlessly. I will eventually use the others for other projects coming up. very good value.

All 5 worked well. Construction is good, well soldered connections. Should last a long time. Diagram included for those who were struggling to figure out the jumper functions.

Works every time easy to hook up and is a great time saver on my projects. The components cost more than the whole thing so I saved time and money

These item cost only a little more then the amp chip works well

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