555 timer monostable mode – One shot

Monostable mode 555 timer, also called one shot, holds the output low until forced high. The output stays high for a period of time and then goes back to low. It is called monostable because low is the one stable condition.

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Assortment of commonly used integrated circuits (IC). I made a lot of videos with them.

Schematic diagram

 

555 timer monostable mode circuit schematic diagram by electronzap electronzapdotcom
555 timer monostable mode circuit schematic diagram by electronzap electronzapdotcom
  • Output (pin 3) stays low (off/0V) until it is forced high/on (close to supply voltage). While the output is low, the LED in this circuit will be off because the other side of the LED is also at 0V (ground).
  • Low signal to trigger (pin 2) sets the output high while a capacitor charges (see next bullet point). The LED is on while the output is high, because the output voltage is as close to the positive supply voltage as it can get.
  • Capacitor connected to threshold (pin 6) and discharge (pin 7) starts charging through a resistor while the output is high.
  • Output stays high until threshold/discharge capacitor reaches 2/3 of the supply voltage. Then the output goes low and the capacitor instantly discharges through pin 7 (discharge pin). Both stay that way (that why they are stable) until the next low pulse to pin 2.



White version of the oscilloscope that I use in many of my recent videos.

Detailed diagram

Basic electronics circuit fragments and simple circuits 10 555 timer monostable mode one shot diagram by electronzap electronzapdotcom
Basic electronics circuit fragments and simple circuits 10 555 timer monostable mode one shot diagram by electronzap electronzapdotcom

Video

555 tmer monostable mode one shot with LED output electronic circuit by electronzap



Power supply I use in my videos.

Related topics:

previous topics:

Transistors will probably be the most challenging components to learn. Understanding them will help you understand all of electronics much better, and help you the most in being creative while designing your own circuits.

Other topics:

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