Series & Parallel Resonance Modes - ECS Inc. International скачать в хорошем качестве

Series & Parallel Resonance Modes - ECS Inc. International

All quartz crystal resonators have a Series & Parallel resonant frequency. This is the Frequency that offers the least amount of impedance to resonation. At this resonant frequency, the crystal appears completely resistive in the circuit. Let’s discuss the Series Resonance Mode In a series L-C circuit the frequency at which the reactance of the inductance and the capacitance cancel each other out, is the resonant frequency. Characteristics of a series resonance circuit include: Minimum impedance and Maximum circuit current Next, let’s look at the Parallel Resonance Mode In a parallel circuit having resistance, inductance and capacitance a parallel resonance (also referred to as anti-resonance) will be achieved. When the resultant current through this parallel combination is in phase with the supply voltage, the parallel resonant circuit will store energy in the magnetic field of the inductor and the electric field of the capacitor. This energy is constantly being transferred back and forth between the inductor and the capacitor which results in a zero current or energy being drawn from the supply. Characteristics of a parallel resonance circuit include: Maximum impedance and Minimum circuit current Lastly, I want to cover Ad justing Frequency, reffered to as “Pulling” Crystals can be "pulled" from this series frequency by adding capacitive reactance in series with the crystal. When operating in combination with an external load capacitance the crystal oscillates in a frequency range slightly above its series resonant frequency. This is the parallel or load resonant frequency. When ordering a parallel crystal, always specify the nominal parallel resonant frequency and specify the circuit load capacitance in Pico Farads. ECS Inc. International 15351 W. 109th Street Lenexa, KS 66219 (913) 782-7787 www.ecsxtal.com engineering@ecsxtal.com