A ceramic resonator is an electronic component that when combined with other appropriate components, can produce oscillations at a specific frequency. It consists of a voltage-variable capacitor that acts in some ways like a quartz crystal. Ceramic resonators are made of high-stability piezoelectric ceramics, generally lead zirconium titanate (PZT) which functions as a mechanical resonator. When voltage is applied, its piezoelectric "vibration behavior" causes an oscillating signal. The thickness of the ceramic substrate determines the resonance frequency of the device.
A typical ceramic resonator package has either two or three connections. They come in both surface mount and through-hole varieties with a number of different footprints. The oscillation takes place across two of the pins (connections). The third pin (if present; typically the center pin) is connected to ground.
Ceramic resonators can be found in many circuit boards as they can be used as the source of the clock signal for digital circuits such as microprocessors where the frequency accuracy is not critical. Quartz has a 0.001% frequency tolerance, while PZT has a 0.5% tolerance. They are also likely to be found in timing circuitry for a wide array of applications such as TVs, VCRs, automotive electronic devices, telephones, copiers, cameras, voice synthesizers, communication equipment, remote controls and toys. A ceramic resonator is often used in place of quartz crystals as a reference clock or signal generator in electronic circuitry due to its low cost and smaller size.
Ceramic resonators look similar to ceramic filters. Ceramic filters are frequently used in the IF stages of superheterodyne receivers.