Generally, oscillations
circuits fall into the following three classes:
- Positive feedback
- Negative resistance
- Transmission time or phase delay
Of the above circuits, the "CERALOCK", quartz resonators and LC
circuits use the first method. Colpitts circuit and Hartley circuit are
typical examples of LC positive feedback and tuned antibonding
oscillation circuit, see below. |
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| <Colpitts circuit> |
<Hartley circuit&g |
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| The above circuits use the
most fundamental transistors as amplifiers. The oscillation frequency
of the Colpitts and Hartley circuit is approximately the same as the
resonant frequency of the circuit comprised of L, CL1 and CL2
and that of the circuit comprised of L1 and L2,
respectively. The oscillation frequency of these circuits is
individually expressed by the following formulae: |
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| <Colpitts circuit> |
<Hartley circuit> |
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To use the
"CERALOCK" in the LC circuit, replace "L" of the LC circuit with the
"CERALOCK" by utilizing the inductance between "fr" and "fa."
Generally, the "CERALOCK" is replaced with "L" of the Colpitts circuit.
The operating principle of the oscillation circuit is described below.
In the feedback circuit as shown on the right, its oscillating
conditions are as follows:
The Colpitts circuit uses an inverting amplifier (theta1=180°), and
also uses "L" and "C" in the feedback circuit for further inversion
(theta2=180°). When the "CERALOCK" is used in the oscillation circuit,
it is based on the same operating principle. To build the Colpitts
oscillation circuit using the "CERALOCK", the method of using an
inverter is most commonly and easily available. |
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