I am facing problem in operate a relay with node mcu .because node mcu provide 3.3 v that is not enough for a 5v relay .What is the best alternative for 5v relay?
I want to control AC and DC load .
The problem is your Arduino is NOT a power supply, so don't attempt to make it power a relay, any relay. Look for a MOSFET or FET that can be turned completely on by your 3.3 volts and have that device operate the relay.
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look for relay module with optocoupler
You need to find a relay that is opto coupled and rated for 3V operation. Many of especially the older design used a power on led in series with the Opto LED and a series resistor. You run out of voltage before you get much light with that design. You can also use an interface chip say in the ULN series such as the ULN2308, they are old school but they work. MOSFETs can also be used.
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