Temporary power shut off

[bonanz]

Hello all,

I'm having a problem figuring out how to go about achieving my desired results for my train's braking system. If a ttl level signal goes high i need to shut the power off to the Linear induction motor coils. These coils may have up to about 1A running to them to drive the train. The amount of current to the coils is controlled by a potentiometer. This potentiometer also has an optional switch so that when the pot is turned all the way down it makes an open circuit between 2 connectors, and once you strart to increase the resistance the switch closes (all separate from the actual pot prongs, but controlled by the pot going to 0). so okay here it is... i want to cutoff the power going to the coils when a digital signal goes high, and for the power to stay off until the pot has been turned all the way to zero opening the switch on the pot. then when the pot is moved up and the switch closes sort of "resetting" the pot. but once its back on, if that same signal goes high again cutoff the current to the coils and wait for teh pot to be "reset."

Sorry if my description is a little confusing, i drew up a quick little thing to try to help visualize it. and remember the coils will be handling pretty high current (1A) so i'm thinking some type of small power transistor inline to the coils being controlled by the switch, some logic, and shutoff signal.

Thanks,
bonanz

[bonanz]

I think i may be able to achieve my desired result with a S-R flip flop. Does anyone have any thoughts on this method? and i've tried looking for an SR flip flop chip number but does it not exist? or would i have to just implement it with a dual package NOR.
Thanks
bonanz

[MP]

Bonanz,
What you are looking for is a RS Latch. You might be able to use a JK flip flop in place of this. Either of these should be readily available as they are both very common devices.

MP