Mosfet in a failsafe switch

[trevrise]

Hi I'm new to all this but have a project were I want to make a failsafe switch for RC use, it must be resistant to vibration.
I want to be able to activate the switch by breaking a connection not making one so I was looking at a depletion mosfet, does anyone have ideas on a circuit, will need to transfer a 6/7 volt DC power supply and be able to carry up to 5 amps.
Thanks

 

[barry]

I don't understand.

A MOSFET is "resistant to vibration", but are you asking about what to use for a mechanical switch?

I don't know what you mean by "activate the switch by breaking a connection". A connection of what, a switch? You mean activate a switch with a switch? Or do you mean turn a mosfet on when a switch opens?

You can use an enhancement mode MOSFET with a pull-up resistor on the gate and a NC switch from gate to common. When the switch opens, the MOSFET will turn on. Is that what you want?

 

[trevrise]

I don't understand.

A MOSFET is "resistant to vibration", but are you asking about what to use for a mechanical switch?

I don't know what you mean by "activate the switch by breaking a connection". A connection of what, a switch? You mean activate a switch with a switch? Or do you mean turn a mosfet on when a switch opens?

You can use an enhancement mode MOSFET with a pull-up resistor on the gate and a NC switch from gate to common. When the switch opens, the MOSFET will turn on. Is that what you want?

That sounds like it, I need the mosfet to turn on when the switch is open not closed. I've had a mechanical switch fail due to vibration witch can have very expensive and dangerous results.
any recommendations on the exact parts.

 

[barry]

Putting a MOSFET in there is not going to solve the problem of the mechanical switch failing.

 

[trevrise]

yes but an open switch like a pin flag is less likely to fail than a closed switch or normal slider.