Driving 110vdc load with mosfet

[iceisfun]

Hello

I need help finding the correct mosfet to drive this load. I have a bunch of these and I want to drive them with a TTL output.

The ones I have tried seem to have some leakage when gate is pulled down to ground.

https://www.amazon.com/dp/B00LVP267S

[Zero999]

All MOSFETs leak some current when off.

You could try using a BJT instead, as it will have a lower cut-off current.

[iceisfun]

I ordered one up to test it out.

Will getting a much bigger mosfet help?

[Zero999]

I ordered one up to test it out.

Will getting a much bigger mosfet help?

No, if anything I would suspect a larger MOSFET would make it worse, not better, since it will have a larger die. A higher voltage, lower current rating may help though.

[T3sl4co1l]

Think dumber.  Put a resistor across the LED load!

Or slightly less dumb -- more usefully -- use an incandescent bulb instead of a resistor?  Might be useful, even if it's just as a pilot light?  Idunno.

Sometimes it's simple things.

Tim

[Zero999]

Think dumber.  Put a resistor across the LED load!

Or slightly less dumb -- more usefully -- use an incandescent bulb instead of a resistor?  Might be useful, even if it's just as a pilot light?  Idunno.

Sometimes it's simple things.

Tim

Duh I don't know why I didn't think of that. lol

It can be a very high value resistor, to minimise the power dissipation, even 1M would probably do.

[macboy]

Think dumber.  Put a resistor across the LED load!

Or slightly less dumb -- more usefully -- use an incandescent bulb instead of a resistor?  Might be useful, even if it's just as a pilot light?  Idunno.

Sometimes it's simple things.

Tim

A small incandescent bulb is a very clever idea, Tim. They have a much lower resistance when off/cold, so would be very effective at shunting the leakage current. Then when fully energized, the resistance goes way up and limits the power consumption. A bulb intended for a small plug-in 120 V nightlight would probably work very well.

[tatus1969]

why are you worried about leakage current? Your 110V LED stripe will be perfectly dark when switched with any suitable MOSFET.

[Zero999]

why are you worried about leakage current? Your 110V LED stripe will be perfectly dark when switched with any suitable MOSFET.

MOSFETs generally have a leakage current of 1µA or more, which is enough to dimly light white LEDs.

All that's needed is a resistor in parallel with the LED rope to reduce the voltage to below the LED strings' forward voltage. An incandescent lamp would do but I suspect it's overkill. A 1M resistor will draw 110µA when the LEDs are on and have <1V across it due to the MOSFET's leakage current.