B4R Question What different between these 2 relay modules

[aeric]

 

[hatzisn]

The left seems to be serial communications (Rx, Tx) capable and the right in 125V AC (USA & Canada) seems to tolerate more current...

 

[aeric]

They are both ESP8266/ESP-01/ESP-01S 5V WiFi Relay Module made in China.
I think both just have different design and uses different relay.

Both are using sealed type structure of relay and have Form C contact form.
Both have 2 VCC, GND or +, - input terminals and 3 output terminals NO, COM, NC.

The left one SRD-05VDC-SL-C (manufacturer: SONGLE) can connect to external input (I guess from RaspberryPi, Arduino or Flipper Zero?) instead of ESP board. According to the datasheet, the contact rating are 10A 250VAC, 7A/10A 240VAC, 10A 125VAC and 10A 28VDC output.

On the right, the JQC-3FF-S-Z (manufacturer: TONGLING) has the printing on the relay doesn't mention about the DC output. It has a reset switch to reset the ESP. According to the datasheet, the contact rating are 10A 250VAC, 15A 125VAC and 10A 28VDC.

So basically I think they can be use for the same purpose since mains power in my country is 220V-240V. I assume I can plug in either ESP01 or ESP-01S to any of them which has 3.3V regulator.

 

[candide]

found in Aliexpress :

https://fr.aliexpress.com/item/32980269299.html?spm=a2g0o.productlist.main.57.1e78evLgevLgrE&algo_pvid=8d6418ae-49ce-4795-b7bf-0bb28d9e615b&algo_exp_id=8d6418ae-49ce-4795-b7bf-0bb28d9e615b-28&pdp_npi=4%40dis%21EUR%212.83%212.83%21%21%212.98%212.98%21%40211b612517083736578627303ea7f8%2166782393789%21sea%21FR%210%21AB&curPageLogUid=aLflvtNHpn4j&utparam-url=scene%3Asearch%7Cquery_from%3A

command of relay is done by esp8266 from message received in wifi

 

[Brian Dean]

If your concern is about the contact ratings then you are right - the two relays are very much the same. As a rule relay contacts are rated at higher AC currents than DC currents because the nature of AC reduces the likelihood of arcing, which is largely what these limits are concerned about. That is why DC control circuits seldom use more than 24 volts whereas AC circuits typically run up to 250 volts.

I am not sure what you mean about 3.3 volts, but yes, these modules generally are rated for a 3.3volt supply. That has nothing to do with the relay ratings which relate to the output power circuit that they control.

 

[aeric]

My concern is more on the compatibility. I just want to confirm that both can swap with ESP-01 and ESP-01S since both are identical. I haven't tested them. Just looking a way to program the ESP without a programmer adapter.

The 3.3v is the voltage for ESP board.

 

[aeric]

I am wondering whether I can directly connect the left relay module to an Arduino UNO and connect to my PC for programming the ESP.

Or can I program the ESP on breadboard connecting to Arduino UNO?

Edit: yes, it is possible. I need to figure out the connection.

 

[thetrueman]

You can use ESP-01 or ESP-01S as you wish since they are identical and have no difference in B4R to program.

 

[aeric]

This thread can use for education purpose for someone looking for more information on the relays.