I remember reading that a Mosfet is opposite of Bipolar transistors,
in that resistance goes up as it heats up, so no thermal runaway.
I have a 15v. supply, with a 5 ohm power resistor, connected to the positive supply rail, a 6volt 3amp dc drill motor then a mosfet heatsinked connected to the neg. rail.
Vgs=4v. Vds=4v. Ids=1.6A. No fan blowing on mosfet.
Vds=6.5v. @ Ids=1.2A with fan blowing on Mosfet.
I'm working on a experimental circuit thats why I need the low Vgs,
and high Vds. to run the motor at slower than normal speeds.
But from this observation it seems like the internal apparent resistance goes up when mosfet is cooler.
And resistance drops when it heats up.
I'm just curious why it works this way when it supposed to have neg. resistance.
in that resistance goes up as it heats up, so no thermal runaway.
I have a 15v. supply, with a 5 ohm power resistor, connected to the positive supply rail, a 6volt 3amp dc drill motor then a mosfet heatsinked connected to the neg. rail.
Vgs=4v. Vds=4v. Ids=1.6A. No fan blowing on mosfet.
Vds=6.5v. @ Ids=1.2A with fan blowing on Mosfet.
I'm working on a experimental circuit thats why I need the low Vgs,
and high Vds. to run the motor at slower than normal speeds.
But from this observation it seems like the internal apparent resistance goes up when mosfet is cooler.
And resistance drops when it heats up.
I'm just curious why it works this way when it supposed to have neg. resistance.