Hi all, what is the signal input voltage of the 5V 4 Channel Relay Module 10A?
I have searched around and am getting mixed answers
I know the relay coils need 5V via the VCC and GND pins.
Can i drive the signals to this directly from say a ESP32 which is 3.3V to the IN1 IN2 etc while also supplying 5V to the coil inputs via GND and VCC? Hoping i dont have to use logic converters etc for the signals Thx
The 5V 4 Channel Relay Module 10A needs a 5V signal voltage, the same as the relay coils. 3.3V should not be enough voltage to fully activate the transistor and trigger the relay. I think its unlikely to damage the board if you try though. Be sure to use a common ground if you do. My suggestion is to use a 5v logic board to keep things simple.
Good luck with your project! Be sure to share your results!
Hi Stephen, Thanks for your reply and clarification.
So for all the 3.3v microcontroller boards (sparkfun thing, esp32, particle photon, etc) everyone just uses logic level converters in their projects to drive any of the relays to step up to 5V signal (or 12v if 12v relay)?
Here is a list of ways that you can do it from a similar question someone asked here: https://electronics.stackexchange.com/questions/213051/how-do-i-use-a-5v-relay-with-a-3-3v-arduino-pro-mini
"1. Just connect it. (The wrong way)**
This might work in some scenario’s, but not this scenario. The relay will draw too much current. For connecting a low current data-connection, it can actually work since the 3.3V might be seen as a logic HIGH.
- The Arduino way.
Buy a TTL Logic Level Shifter - https://www.sparkfun.com/products/12009
This little board will change output 5V, when given 3.3V at the signal in. The only problem, however, is that you will need a 5V on the input of the board.
- The Electronics way.
You can easily use a transistor or mosfet to switch another (higher) current. This doesn’t really differ that much from option 2, but it’s a litte more complicated, but cheaper.
- Another way, like a boss.
Search Stack-Exchange/Google for people with the same problem. I’ve found that you can actually step up 3.3V to 5V, so that you won’t need a 5V supply. https://www.circuitsathome.com/dc-dc/33v-to-5v-dc-dc-converter
Get a relay that works on your battery voltage and can be triggered from 3.3V. You could consider something like this: http://www.ebay.com/itm/5PCS-3V-3-3V-Relay-High-Level-Driver-Module-optocouple-Relay-Module-for-Arduino-/331413255692
It has an optocoupler, to isolate the arduino from the actual relay. It might be better to get one that actually works on your battery voltage range. So that you can hook it up to the battery (and the signal pin to the Arduino). So the coil isn’t activated directly by the arduino, which would draw too much current."