First post here. Dabbler in electronics but seriously behind the times now.
I need a circuit to deliver 24 VDC pulses once a minute to an old railway clock. The pulses advance the minute hand. Each pulse should be one or two seconds long and preferably damped. Power is around 20-25 mA.
I already have a circuit that will do that, almost. It works most of the time. That is not very good for a clock. It uses a reed switch tripped by an AC synchronous motor which controls an FET. The diagram is attached to this post.
There are problems with the existing design. The three sections of interest are
- Power supply - the voltage divider is not providing the power needed
- A timer chip would be much better than the mechanical 1-minute switching section
- It would be nice to damp the power going to the clock so the armature works quietly.
I would appreciate suggestions for a better circuit.
I need a circuit to deliver 24 VDC pulses once a minute to an old railway clock. The pulses advance the minute hand. Each pulse should be one or two seconds long and preferably damped. Power is around 20-25 mA.
I already have a circuit that will do that, almost. It works most of the time. That is not very good for a clock. It uses a reed switch tripped by an AC synchronous motor which controls an FET. The diagram is attached to this post.
There are problems with the existing design. The three sections of interest are
- Power supply - the voltage divider is not providing the power needed
- A timer chip would be much better than the mechanical 1-minute switching section
- It would be nice to damp the power going to the clock so the armature works quietly.
I would appreciate suggestions for a better circuit.
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