Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Momentary relay or transistor?

  1. Apr 18, 2012 #1
    I am working with a kit circuit that I ordered online. The circuit triggers a relay when it "hears" a loud noise. I am going to hook the relay to a strobe to capture the moment of impact. with my camera. The circuit by design triggers and "holds" the signal until it hears it again. This will cause my strobe to fire repeatedly until it is tripped again. Is there such thing as a relay or transistor that will fire momentarily when it gets a signal? Do I just need to get a trigger circuit?
  2. jcsd
  3. Apr 19, 2012 #2
    You can use 555 timer in monostable configuration.
    555 timer can work as monostable or astable oscillator.
    The pulse width is adjusted using capacitor and resistor, you can see the configuration for monostable on the web.
    The output signal from your circuit turns on a transistor that turns on the 555 timer.
    Once the timer is on, it creates a pulse with width calculated by your capacitor and resistor.
    Then the outupt of the 555 timer should switch a transistor to drive the output relay.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook