• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
  • Radioddity is giving away a radio for Father's Day! Click Here for details!
oneshot
unit_399

oneshot

  • Media owner unit_399
  • Date added
@linearone looks like a one-shot timer like the file name suggests.

With the switch open, both sides of the capacitor are pulled to the supply voltage. With the base high, the PNP transistor is off. When the switch is closed, one side of the capacitor goes to ground which temporarily pulls the other side down with it. When that happens, the base of the transistor is momentarily pulled down too, which turns on the transistor.

Two things turn off the transistor. With the switch held closed, the RC time constant will turn it off as the capacitor charges to 11.3v. It will also turn off (immediately, really fast) if the switch is opened since the left resistor pulls the - side of the cap to the + rail. With 12v already across the cap, this results in more than 12v at the base until the cap discharges back to its initial state.

Whatever this is for, it is triggering a short event the moment the switch is pressed and turns off shortly after.
 

Media information

Album
one-shot trigger
Added by
unit_399
Date added
View count
1,383
Comment count
2
Rating
0.00 star(s) 0 ratings

Share this media