L1 and C1 also resonate with the parallel capacitor C2.
#Quartzcrystal series#
Due to this series frequency a secondary frequency point recognized with the parallel resonance.
This operating frequency is referred as crystals series frequency (fs). The series circuit which consists one capacitor, one resistor and one inductor, symbolize the controlled behavior and stable operations of the Crystal and the parallel capacitor, C2 represents the parallel capacitance of the circuit or the equivalent crystal.Īt the operating frequency the C1 resonate with the inductance L1. C1, L1, R1 is connected in series and the C2 connected in parallel. As we can see, 4 passive components are used, two capacitor C1 and C2 and one Inductor L1, Resistor R1. In the upper image, left circuit represents the equivalent circuit of Quartz Crystal, shown in the right side. This specific frequency for the specific crystal is called characteristic frequency.
Once it is shaped and controlled, the frequency produced is fixed, the fundamental frequency cannot be changed into other frequencies. The metalized surfaces are made for electrical connections, and the quartz physical size and density also the thickness is tightly controlled as the changes in shape and size directly effect in the oscillation frequency. The quartz crystal is made from thin piece of quartz wafer tightly fitted and controlled between two parallel metalized surfaces. This is the symbol of Crystal Oscillator. Quartz Crystal and its Equivalent Circuit These changes produce very stable vibration, and as a Piezo-electric effect produces the stable oscillations. When voltage source is applied across it, it will change shape and produce mechanical forces, and the mechanical forces revert back, and produce electrical charge.Īs it convert energy electrical to mechanical and mechanical to electrical it is referred as Transducers. It produces a characteristic, identified as Piezo-electric effect. It reacts when a voltage source applied to quartz crystal. Quartz is mineral composed of silicon and Oxygen atoms. In such situation, the Quartz Crystal is used. The stability can be improved to a certain level in case of RC and RLC circuit, but still the improvement is not sufficient in specific cases. The temperature changes affect the load and power supply line which in turn affects the stability of the Oscillator circuit. In case of RC (Resistor-Capacitor) or RLC (Resistor-Inductor-Capacitor) Oscillators, they are not good choice where stable and accurate oscillations are needed. A proper good oscillator produces stable frequency. An oscillator is a mechanical or electronic construction which produces oscillation depending on few variables. In our previous RC Phase Shift Oscillator and Wein Bridge Oscillator tutorials, we get fair idea about what is an Oscillator.
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