# Detailed explanation of ceramic resonator (CERALOCK) oscillation circuit

The above circuit uses the most basic transistor as an amplifier. The oscillation frequency of the Colpitts and Hartley circuit is almost the same as the resonant frequency of the circuit composed of L, CL1, L2 or the circuit composed of L1, L2. The oscillation frequencies of such circuits are respectively expressed by the following equations.

Generally, oscillator circuits can be divided into the following three types:

1. Positive feedback circuit
2. Negative Impedance Circuit
3. Transfer time or phase delay circuit

CERALOCK®, quartz crystal, LC circuits belong to the first category of circuits mentioned above. Colpitts and Hartley circuits are typical LC positive feedback circuits and tuned anti-bonding oscillator circuits as follows:

The above circuit uses the most basic transistor as an amplifier. The oscillation frequency of the Colpitts and Hartley circuit is almost the same as the resonant frequency of the circuit composed of L, CL1, L2 or the circuit composed of L1, L2. The oscillation frequencies of such circuits are respectively expressed by the following equations.

Use CERALOCK® in LC circuit, replace “L” in LC circuit with CERALOCK®, use “fr” to “fa” inductance. Typically, CERALOCK® is replaced with an “L” in a Colpitts circuit.

The working principle of the oscillator circuit is described as follows. For the feedback circuit shown above, the oscillation 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 oscillator circuit adopts CERALOCK®, its working principle is the same as above. In order to utilize CERALOCK® in Colpitts oscillator circuits, inverters are usually used.