Other Uses

The previous sections cover the basic operating modes of the 555. Beyond this there are a staggering variety of uses this little chip has found since it was released in 1972. There are some sources of projects in the References section.

One place 555s (actually a 558: 4 555s on a single 16-pin chip) were used in early microcomputers (notably the Apple ][ and the IBM PC) was the game controller interface. By using a 555 in monostable mode and using a potentiometer in place of the timing resistor, software could trigger the timers and measure the length of the output pulses. The pulse length was proportional to the value of the resistor, and thus the position of the paddle/joystick.

This guide was first published on Mar 13, 2018. It was last updated on Mar 13, 2018. This page (Other Uses) was last updated on Aug 27, 2019.