Diodes across limit switches on a motor to allow reverse after stopping

I'm trying to make a simple limit system for a little gearbox. I was thinking I could use an arm that hits two microswitches (one on each wire) set up to give me the desired rotation, and if I used diodes across the microswitches in the opposite direction, that would let the motor still be reversed after hitting the limit. The motor is 12V, and will pull about 2 amps maximum stall current. My question is, is this a workable solution to use diodes in this fashion? If so what diodes should I use?

thanks for any advise.

torriem: I'm trying to make a simple limit system for a little gearbox. I was thinking I could use an arm that hits two microswitches (one on each wire) set up to give me the desired rotation, and if I used diodes across the microswitches in the opposite direction, that would let the motor still be reversed after hitting the limit. The motor is 12V, and will pull about 2 amps maximum stall current. My question is, is this a workable solution to use diodes in this fashion? If so what diodes should I use?

thanks for any advise.

Yes a common application. A diode blocks current flow when reaching one end of travel. Reversing the applied polarity allows motor to then turn opposite direction until reaching the opposite end of travel. Diode don't have to carry full motor current as they are used only to block flow, however the contacts of the limit switch do need to be rated at, or better yet well above, the actual maximum motor current rating. Extra set of contacts on each switch can be very useful so an attached micro knows what state the system is in, fully in one direction or fully in opposite direction, or somewhere between (possibly moving).

I think the diodes should be rated for more than the motor stall current. If you look at the attached schematic, in this configuration the diode carries the stall current (at least momentarily) when the limit switch is open and the motor starts up in the reverse direction. See the attached schematic.

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Some diodes have a pulse rating, you can use that for the stall current, ensure the continuous current rating is adequate for normal load conditions. However you could conceivable have a failure mode where the motor is jammed and the switch is stuck open, leading to the diode failing. Then its really being a fuse (which isn't necessarily bad if the alternative is wiring melting)

Below is a diode/limit switch setup. You can get rectifier diodes at Radio Shack that can pass 1A and more.