transistors motorcycle alarm.

I have a gps103a that has + and - door trigger inputs.

I'd like to use transistors to have a "wire cut" trigger on the neg door input.

I'm putting a big loop of continous wire on the motorcycle cover and I want my alarm to go off if the circuit is broken.

I don't want to use relays, because I need to keep the power consumption to the bare minimums. MC battery is very short on juice, and the GSM and GPS alarm are already pushing it.

Thanks 12v!

Any FET or MOSFET or transistor inverter circuit.
The grounded or +12V connected loop keeps the transistor off; when the loop breaks a pull-up or -pull-down resistor (to the opposite ie, +12V or GND rail) turns on the transistor, or vice versa if desired (door inputs are usually a -ve going or GND trigger, nit a wire cut).

Make it DC sensing (a low pass filter) to prevent RFI triggering.

Or a DEI 502T for the less glamorous solution.

Oldspark thank you, do you have an example circuit i can wire up?

Sorry for asking to be spoon fed.

Is the transistor even necessary? Use a high value resistor (>10K ohms) to tie your (-) door input to ground. Then, connect your loop through (+) voltage. You may want to add a 10K ohm resistor in line with the (+) feed as a current limiter but you may need to play with the values to get them to work together and trigger properly.

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Kevin Pierson

X2

I think you want to use the pull-up resistor on the (+) trigger input.
The wire loop is used to connect this input to ground. Cut the loop, +12 volt flows through resistor triggering input, not to ground. Your standby current draw is the battery voltage divided by pull-up resistor value...ohms law.