Electronics pp 294-327 | Cite as


  • G. H. Olsen


An oscillator is an instrument for producing voltages that vary in a regular fashion; the waveforms of the voltages are repeated exactly in equal successive intervals of time. In many cases the waveform of the output voltage is sinusoidal and the oscillator is then called a sinewave generator or harmonic oscillator. Those instruments that produce repetitive waveforms that are square, triangular or sawtooth in shape are called relaxation oscillators. The term ‘relaxation’ is used because during the generation of the waveform there is a period of activity in which there is a sharp transition from one state to another. This period is then followed by a relatively quiescent one, after which the cycle is repeated. Several examples of relaxation oscillators occur in nature, the most common one being the heart. During the operation of the heart there is a period of activity in which the blood is pumped through the heart chambers and out into the arteries. This period is followed by one in which the heart muscles relax and prepare for the next burst of activity.


Anode Current Anode Voltage Relaxation Oscillator Grid Voltage Resonant Circuit 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Nyquist, H. ‘Regeneration theory’. Bell Syst. Tech. J. 1932, 11, 126.CrossRefMATHGoogle Scholar
  2. 2.
    Jackson, A. ‘A simple high frequency transistor recorder for chromatography’. J. Chem. Education, 1965, 42, p. 447 (Aug.).ADSCrossRefGoogle Scholar
  3. 3.
    Heising, R. A. Quartz Crystals for Electrical Circuits — Their Design and Manufacture. D. Van Nostrand, 1946.Google Scholar
  4. 3a.
    See also Terman, F. E. Electronic and Radio Engineering, p. 506 et seq., McGraw-Hill, 1955.Google Scholar
  5. 4.
    Baxandall, P. J. ‘Transistor crystal oscillators and the design of a 1Mc/s oscillator circuit capable of good frequency stability’. J.I.E.R.E., 1965, 29, No. 4 (April).Google Scholar
  6. 5.
    ‘Wide Range Transistor Phase-Shift Oscillator’. Application Note No. 1. Ferranti Ltd.Google Scholar

Suggestions for Further Reading

  1. Pulse and Digital Circuits by J. Millman and H. Taub, McGraw-Hill, 1956.Google Scholar
  2. Waveforms by B. Chance, V. Hughes, E. F. MacNichol, D. Sayne, and F. C. Williams, McGraw-Hill, 1956.Google Scholar
  3. ‘Multivibrator Design’ by Foss, R. C. and Sizmur, M. F., Wireless World, 1961, 67, No. 4 (April), p. 221 and No. 5, May, p. 257.Google Scholar

Copyright information

© G. H. Olsen 1968

Authors and Affiliations

  • G. H. Olsen
    • 1
  1. 1.Physics Dept.Rutherford College of TechnologyUK

Personalised recommendations