NOYITO Isolated MOS FET Field Effect Transistor Module Optocoupler Isolation (Pack of 2) (100V 9.4A FR120N)

Used on a 10A system for ignition switching and couldn’t be happier with it. Small and compact and does what is advertised.

Every other version of this has blown in my application but this one is holding. I'm sure all voltage and current ratings are skewed on stuff like this but I can at least say that this one is stronger than the next step lower.

One of the 2 boards I received wouldn't work. Glad I tried the other board before thinking that it just wasn't working.

Excelente

Look up the IR part. It's rated for 161A at 25C -- based on junction temperature, *NOT* package limitation, which is 30A. Even if the package could pass 161 amps continuous -- a physical impossibility -- the resulting power dissipation would be around 85W. That kind of heat would melt that little board down into a puddle.I hate it when these scumbags use numbers that can't possibly work out to advertise their kaka.

The FR120N MOSFET has a pretty high V_GS threshold, if you connect up a load that's under about 7V, the MOSFET won't actually fully switch.The solution is to find the 4.7 kohm pull-down resistor on the gate and replace it with something like 200 kohm. Also, it will never work with a load below 5V.Note: while it specifies that the input voltage range is 3V~5V, the current limiting resistor on the input is about 1 kohm and applying 12V to it resulted in about 10mA of current through the LED. This should be fine for the PC817, which is rated for 50mA maximum at the input, most of the testing done at 20mA