555
From HvWiki
The 555 is a device for generating time delays or oscillation. Additional terminals are provided for triggering or resetting if desired. In the time delay mode of operation, the time is controlled by one external resistor and capacitor. For astable operation as an oscillator, the free running frequency and duty cycle are accurately controlled with two external resistors and one capacitor. The circuit may be triggered and reset on falling waveforms, and the output circuit can source or sink up to 200 mA or drive TTL circuits.
There are both CMOS and bipolar versions of the 555 and the specifications are not the same. There are even variations between different manufacturers.
Contents |
Common Setups
Basic Astable
Basic Monostable
Applications
- Timing
- Pulse generation
- Sequential timing
- Time delay generation
- Pulse width modulation
- Pulse position modulation
- Linear ramp generator
Rigging the 555 to go 50% duty
This circuit is simple and easy to build, however its letdown is that if the load changes the frequency will change.
