I would like to be able to use a MOSFET, or other FET, or FETs (plural) ) to simulate/replace a relay contact.
The problem I am having (I am a beginner), is that you need a certain voltage between gate and source to turn it on, eg, say 4 Volts. This means that the gate must be 4V higher than the source which is sometimes impossible, but it would not be a problem with a simple relay.
I attach a schematic to demonstrate the problem. I chose a random MOSFET with very low Ron from the list on the simulator. The mosfet needs to switch very close to the Vs (12V - 11.5V) but that requires its gate to be 3-4 Volts over the supply!
Any help appreciated.
PS In the end I will buy and use an old fashion relay, but until it arrives I would like to experiment.
The problem I am having (I am a beginner), is that you need a certain voltage between gate and source to turn it on, eg, say 4 Volts. This means that the gate must be 4V higher than the source which is sometimes impossible, but it would not be a problem with a simple relay.
I attach a schematic to demonstrate the problem. I chose a random MOSFET with very low Ron from the list on the simulator. The mosfet needs to switch very close to the Vs (12V - 11.5V) but that requires its gate to be 3-4 Volts over the supply!
Any help appreciated.
PS In the end I will buy and use an old fashion relay, but until it arrives I would like to experiment.
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