Circuit Library

This circuit creates a light that "runs" back and forth using a 555 timer and a decade counter. It's effect is similar to the light bar on the car from the old television show Knight Rider. It's a really fun circuit to build. I once built a larger version of this for the inside of a party bus when I was a teenager. Unfortunately, I broke it the first day because I increased the voltage too much! But that's another story...

A simple project that counts the number of times you've pressed the button. Can be used as a scoreboard display for a game. Or to keep tracks of things like how many cups of coffee you've had today.

This "machine gun" circuit generates a sound that mimics the sound of a toy machine gun. It is based around a 555 timer IC in a feedback loop. Check out [this demo video](https://youtu.be/wSN8_ChDztw) to hear the circuit in action.

Here's how to build a simple LED blinker using a 555 timer. The 555 timer is configured as an astable multivibrator, which means the output will turn on and off repeatedly. With the chosen values, it will turn on and off about five times per second. Since the LED is connected to the output, it blinks =)