Relaxation Oscillator: Difference between revisions
| Line 6: | Line 6: | ||
==Uses== |
==Uses== |
||
This type of circuit was used as the [[timebase]} in early [[oscilloscope]]s and variants of this circuit find use in [[stroboscopes]] used in machine shops and nightclubs. Electronic camera flashes are a monostable version of this circuit, generating ''one cycle'' of the sawtooth, the rising edge as the flash capacitor is charged and the rapid falling edge as the capacitor is discharged and the flash is produced upon receiving the firing signal from the shutter button. |
This type of circuit was used as the [[timebase]} in early [[oscilloscope]]s and variants of this circuit find use in [[stroboscopes]] used in machine shops and nightclubs. Electronic camera flashes are a monostable version of this circuit, generating ''one cycle'' of the sawtooth, the rising edge as the flash capacitor is charged and the rapid falling edge as the capacitor is discharged and the flash is produced upon receiving the firing signal from the shutter button. |
||
Use as a timebase in oscilloscopes was discontinued when the much more linear [[Miller Integrator]] timebase circuit using "hard" valves, (vacuum tubes), was developed. |
|||
==References== |
|||
Radio and Electronic Laboratory Handbook, M.G. Scroggie 1971, ISBN 0-592-05950-2 |
|||
[[Category:Oscillators]] |
[[Category:Oscillators]] |
||
Revision as of 14:02, 7 April 2009
A relaxation oscillator is a simple electronic circuit used to generate a non-linear sawtooth waveform.
Description
The circuit consists of a resistor and capacitor wired in series and connected to a D.C. voltage source. A cathode glow lamp, usually containing neon at low pressure, is connected in parallel with the capacitor. When energized the capacitor commences to charge via the resistor, the voltage rising in a non-linear fashion across the capacitor and cathode glow lamp. When the striking voltage of the cathode glow lamp is reached it suddenly conducts discharging the capacitor, emitting a bright flash and extinguishing. The capacitor is not totally discharged and commences to charge again via the resistor to produce the second cycle of the sawtooth waveform. The cycle repeats until the voltage source is disconnected. A second resistor with a value of a few hundred ohms is often placed in series with the cathode glow lamp to limit the current from the discharging capacitor and prevent the electrodes of the lamp rapidly sputtering away. If the waveform is to be synchronized with another signal, the cathode glow lamp is replaced with a triode thyratron, and the synchronizing pulses are applied to the grid of the thyratron.
Uses
This type of circuit was used as the [[timebase]} in early oscilloscopes and variants of this circuit find use in stroboscopes used in machine shops and nightclubs. Electronic camera flashes are a monostable version of this circuit, generating one cycle of the sawtooth, the rising edge as the flash capacitor is charged and the rapid falling edge as the capacitor is discharged and the flash is produced upon receiving the firing signal from the shutter button. Use as a timebase in oscilloscopes was discontinued when the much more linear Miller Integrator timebase circuit using "hard" valves, (vacuum tubes), was developed.
References
Radio and Electronic Laboratory Handbook, M.G. Scroggie 1971, ISBN 0-592-05950-2