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Electronic circuits that use the 555 Timer

555 Timer Circuits

555 Timers are fun and a great way to start learning electronics


When output pin 3 is HIGH, the 220n charges through the 220k to 6v. When pin 3 is LOW, the 220n discharges through the 220k to 0v. Pressing the switch upsets the 3v created by the two 10k voltage dividers, triggering the flip flop inside the 555 and changing the state of the output from HIGH to LOW or vice-versa. The output of the 555 drives a transistor to turn a globe on and off.
The second circuit is a Memory cell and is the basis of the memory in a computer. The SET button turns on the globe and the RESET button turns the globe off.
It works like this: When the circuit is turned on, pin 6 does not see a high and pin 2 does not see a low, so the 555 starts in reset mode.

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