555 Timer, 556 Timer

The 555 Timer Chip The 555 is an integrated circuit (chip) implementing a variety of timer and multivibrator applications. The IC was designed and invented by Hans R. Camenzind. It was designed in 1970 and introduced in 1971 by Signetics (later The 556 Timer Chip acquired by Philips). The original name was the SE555/NE555 and was called "The IC Time Machine". It is still in wide use, thanks to its ease of use, low price and good stability. As of 2003, 1 billion units are manufactured every year. (wikipedia)

The 556 is the dual version of the chip.

555, 556 Pinouts

555 Basic Specifications	(for LM555C version) Supply Voltage: 4.5v min, 16v max Current Draw: 3-6ma @ 5vDC, 10-15ma @ 15 vDC
555 Oscillator Schematic A minimal parts-count oscillator that will go from LFO to tone oscillator. Change C1 and VR1 values to change range. Coarse + Fine Tempo/Rate: Add a small value (ie. B1K) pot in series with the standard rate pot for fine tuning the rate.
555 Toy Organ Build a fun little music maker.

Astable and monostable operations

Basic Astable Oscillator Configuration

555 Astable Oscillator Schematic

Basic Monostable Oscillator Configuration

555 Monostable Oscillator Schematic

Stepped Tone Generator

from the classic Forrest Mimms circuit. This was re-published a while ago as the Atari Punk Console. Output options are shown for both speaker and line level.

556 Stepped Tone Generator