Blocking oscillator

A blocking oscillator is the minimal configuration of discrete electronic components which can produce a free-running signal, requiring only a capacitor, transformer, and one amplifying component. The name is derived from the fact that the transistor (or tube) is cut-off or "blocked" for most of the duty-cycle, producing periodic pulses. The non-sinusoidal output is not suitable for use as a radio-frequency local oscillator, but it can serve to flash lights or LEDs, and the simple tones are sufficient for applications such as alarms or a morse-code practice device. Some cameras use a blocking oscillator to strobe the flash prior to a shot to reduce the red-eye effect.

Due to the simplicity of the circuit, it forms the basis for many of the learning projects in commercial electronic kits. A secondary winding of the transformer can be fed to a speaker, a lamp, or the windings of a relay. A potentiometer placed in parallel with the timing capacitor permits the frequency to be adjusted, but at low resistances the transistor will be overdriven, and possibly damaged. The output signal will jump in amplitude and be greatly distorted. The frequency of the oscillator is also affected by the supply voltage.

External links

*" [http://www.du.edu/~etuttle/electron/elect37.htm The blocking oscillator] ", web page by [http://www.du.edu/~jcalvert/ James B. Calvert] . An elementary (no mathematics) and informative description of various blocking oscillator circuits, employing BJTs and Triodes.
*" [http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1082353 Circuit models to predict switching performance of nanosecond blocking oscillators] ", J. McDonald, IEEE [http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=8147 Transactions on Circuits and Systems] , 1964, Volume 11, Issue 4, 442- 448. A paper deriving some circuit models in order to predict the switching performance of BJT blocking oscillators.


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  • blocking oscillator — blokinggeneratorius statusas T sritis automatika atitikmenys: angl. blocking generator; blocking oscillator vok. Blocking Generator, m; Blockingoszillator, m; Sperrschwinger, m rus. блокинг генератор, m pranc. oscillateur à blocage, m;… …   Automatikos terminų žodynas

  • blocking oscillator — blokinggeneratorius statusas T sritis fizika atitikmenys: angl. blocking generator; blocking oscillator; self quenching generator vok. Blockinggenerator, m; Blockingoszillator, m; Sperrschwinger, m rus. блокинг генератор, m pranc. oscillateur à… …   Fizikos terminų žodynas

  • monostable blocking-oscillator — laukiantysis blokinggeneratorius statusas T sritis automatika atitikmenys: angl. monostable blocking oscillator; single shot blocking oscillator vok. monostabiler Blockinggenerator, m; monostabiler Sperrschwinger, m rus. блокинг генератор с одним …   Automatikos terminų žodynas

  • single shot blocking-oscillator — laukiantysis blokinggeneratorius statusas T sritis automatika atitikmenys: angl. monostable blocking oscillator; single shot blocking oscillator vok. monostabiler Blockinggenerator, m; monostabiler Sperrschwinger, m rus. блокинг генератор с одним …   Automatikos terminų žodynas

  • unstable blocking-oscillator — nenuostovusis blokinggeneratorius statusas T sritis radioelektronika atitikmenys: angl. unstable blocking oscillator vok. astabiler Blockingoszillator, m rus. нестабильный блокинг генератор, m pranc. oscillateur à blocage astable, m …   Radioelektronikos terminų žodynas

  • Blocking-Generator — blokinggeneratorius statusas T sritis automatika atitikmenys: angl. blocking generator; blocking oscillator vok. Blocking Generator, m; Blockingoszillator, m; Sperrschwinger, m rus. блокинг генератор, m pranc. oscillateur à blocage, m;… …   Automatikos terminų žodynas

  • blocking generator — blokinggeneratorius statusas T sritis automatika atitikmenys: angl. blocking generator; blocking oscillator vok. Blocking Generator, m; Blockingoszillator, m; Sperrschwinger, m rus. блокинг генератор, m pranc. oscillateur à blocage, m;… …   Automatikos terminų žodynas

  • blocking generator — blokinggeneratorius statusas T sritis fizika atitikmenys: angl. blocking generator; blocking oscillator; self quenching generator vok. Blockinggenerator, m; Blockingoszillator, m; Sperrschwinger, m rus. блокинг генератор, m pranc. oscillateur à… …   Fizikos terminų žodynas

  • Oscillation — For other uses, see oscillator (disambiguation) and oscillation (mathematics). An undamped spring–mass system is an oscillatory system. Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a… …   Wikipedia

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