What is Oscillation?
• repetitive variation of
some measure about
a central value
• swinging pendulum an
d AC power.
• An electronic circuit that produces a
repetitive, oscillating electronic signal.
• Oscillators are often characterized by
the frequency of their output signal:
• Oscillators designed to produce a
high-power AC output from a DC
supply are usually called inverters.
• There are two main types of electronic
oscillator: the linear or harmonic
oscillator and the nonlinear
or relaxation oscillator.
• produces a sinusoidal output.
• There are two types of linear oscillators:
Feedback oscillator Negative resistance
• produces a non-sinusoidal output.
• Types of relaxation oscillator circuits
delay line oscillator
rotary traveling wave oscillator
• Harmonic Oscillator
Harmonic oscillators, also known as sine-wave
oscillators, are used in transmitters to create
carrier waves, waveforms created for the
purpose of transmitting information. They are
also used in radios as a way of changing the
modulation of information-carrying waveforms to
allow the device (the radio receiver) to receive
and interpret them.
• Relaxation Oscillator
Relaxation oscillators, also known as non-
sinusoidal oscillators, are often found in
computers and televisions as timers and
switches. The jagged waveforms created by
relaxation oscillators are caused by abrupt,
arrhythmic events, such as the sudden
discharge of a capacitor. Variations of this type
of oscillator can also be found in strobe lights
and electronic camera flashes.
• Crystal-controlled Oscillator
Crystal-controlled oscillators are a form of
relaxation oscillator. The distinction between the
two is that a crystal-controlled oscillator uses a
crystal in place of a standard inductor-capacitor
circuit to improve waveform frequency stability.
They are used in a number of technical
electronic devices, such as MTI radars, wireless
base stations, telecom timing modules, satellite
terminals and ethernet transceivers.