Page 3 – 555 timer basic circuits

The 555 timer is a very well known integrated circuit (IC) that is included in a lot of kits. There are 3 basic modes listed below.

Become a Patron! https://www.amazon.com/shop/electronzapdotcom https://www.youtube.com/electronzap

Basic circuits

555 timer pin layout illustrative diagram by electronzap electronzapdotcom
555 timer pin layout illustrative diagram by electronzap electronzapdotcom
  • Bistable
  • Monostable
  • Astable

Plus I like the following simple 555 timer circuit:

  • Schmitt trigger.

Bistable

Simple 555 timer bistable mode flip flop alternating LEDs circuit schematic diagram by electronzap electronzapdotcom
Simple 555 timer bistable mode flip flop alternating LEDs circuit schematic diagram by electronzap electronzapdotcom

Affiliate link ad. This is the power adapter I used for my breadboard power supplies and other power needs.

 

Output goes high when set/trigger button is pressed. Output goes low when reset button is pressed. Output is always low if reset button is held low.

Quick 555 timer bistable flip flop mode circuit schematic to breadboard build by electronzap

Monstable

Simple 555 timer monostable one shot mode circuit schematic diagram by electronzap electronzapdotcom
Simple 555 timer monostable one shot mode circuit schematic diagram by electronzap electronzapdotcom

Briefly pressing the button lights the LED for a period of time set by the capacitor and it’s charging resistor.

Direct link to video below.
Quick 555 timer monostable one shot mode lighting an LED circuit schematic to breadboard build

Astable

Simple 555 timer astable multivibrator mode circuit schematic diagram by electronzap electronzapdotcom
Simple 555 timer astable multivibrator mode circuit schematic diagram by electronzap electronzapdotcom

Astable keeps the output going high and low (on and off) indefinitely. One LED and protective resistor at the out and headed to either ground or the supply voltage (Vcc) will keep flashing on and off at a speed set by the capacitor at pin 6 and timing resistors.

An LED with protective resistor can go from the output to ground while another LED with protective resistor can go from the output to the Vcc. They will alternate which one is on and off at any given time.



Affiliate link ad. Kit has lots of well known ICs, including the NE555 used in my videos.

Quick 555 timer astable multivibrator mode circuit schematic to breadboard build by electronzap

Schmitt trigger

Simple 555 timer Schmitt trigger logic inverter circuit schematic diagram by electronzap electronzapdotcom
Simple 555 timer Schmitt trigger logic inverter circuit schematic diagram by electronzap electronzapdotcom

Schmitt triggers use an input voltage to switch the high/low or on/off output. If the voltage is high enough then the output is in one condition, and if the voltage is low enough then the output is in another condition. The Schmitt trigger input has a middle ground input voltage area (hysteresis) that keeps the output in the last condition it was put into.

 

Quick 555 timer based schmitt trigger inverting logic switch circuit schematic diagram to breadboard



As an Amazon Associate I earn from qualifying purchases.

  • Information on this site is not guaranteed to be accurate. Always consult the manufacturer info/datasheet of parts you use. Research the proper safety precautions for everything you do.