Ideal would be mountable in a DB board on a DIN rail.

Something like a "single shot non-latching switch"

A normal button like a push button remains closed for as long as I hold my finger on it. What I'm looking for is a switch that requires me to remove my finger and press again if I want another brief connection (pulse).

I want to use it as a trigger.

Alternatively, there must be safety applications where things should not just restart when the power comes back on after a power failure.

If the power fails, then manual intervention is required to restore the power, and that can't be overridden by physically keeping the switch in the on position.

Any suggestions?

  • \$\begingroup\$ Might this help? electronics.stackexchange.com/questions/416929/… \$\endgroup\$
    – rdtsc
    Commented Jan 2, 2023 at 19:11
  • 1
    \$\begingroup\$ What's a DB board? Try looking for a monostable. \$\endgroup\$
    – Andy aka
    Commented Jan 2, 2023 at 19:17
  • \$\begingroup\$ Distribution board \$\endgroup\$
    – Maxcot
    Commented Jan 2, 2023 at 19:27
  • \$\begingroup\$ distribution board board? \$\endgroup\$
    – jsotola
    Commented Jan 2, 2023 at 20:05

1 Answer 1


There are many pulse relays available for industrial control systems. These will come in standard industrial control voltages, 24 VDC, 110 VAC and 230 VAC.


simulate this circuit – Schematic created using CircuitLab

Figure 1. A simple pulse circuit.

When SW1 is pressed OUT will turn on until RLY1 is energised (which will be very quickly). This may or may not be adequate for your application.

The industrial devices mentioned above will have adjustable pulse times.

  • \$\begingroup\$ And if someone wants to hack the system, and glue SW1 down, with some tape...? This is what I'm trying to prevent \$\endgroup\$
    – Maxcot
    Commented Jan 2, 2023 at 18:54
  • 1
    \$\begingroup\$ Work it out! RLY1 will remain energised and OUT will be disconnected (switched off). \$\endgroup\$
    – Transistor
    Commented Jan 2, 2023 at 19:56
  • \$\begingroup\$ You can also make one out of electronics but I guess that might not be suitable for a distribution board kind of application \$\endgroup\$ Commented Jan 2, 2023 at 22:19
  • \$\begingroup\$ Might be with pointing out that the industrial device would (or could) be a simple delay timer if wired this way. \$\endgroup\$ Commented Jan 3, 2023 at 2:48

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