Input characteristics
The 12 Volt relay module has a jumper to select between active high or active low.
With the jumper on active high (H), the relay can be driven by an ESP32 CPU that runs on a voltage of only 3.3V. Measurements reveal that (when increasing the input voltage) the relay attracts (click) at 2.4V, and then falls back off (clack) at 1.7V. These values suit a 3.3V micro-controller well.
The optocoupler
The printing on the optocoupler hints to a TLP280 type.
Properties
- 12V power supply
- 1 relay SPDT (Single Pole, Double Throw)
- with jumper on L: make input 0V to activate relay = active low input
- with jumper on H: make input >3V to activate relay = active high input
- module type number: YYG-2
- a LED indicates relay on
- a LED indicates power supply presence
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