Description of the capacitance function of the multimeter
Electricians in the digital multimeter, according to the role of capacitors in the circuit capacitor's basic role is to charge and discharge, but by this basic charge and discharge extended by many circuit phenomena, making capacitors have a variety of different uses, such as in electric motors, electricians use it to produce phase shift; in the photographic flash, it is used to produce high-energy instantaneous discharge and so on; and in electronic circuits, capacitors Different nature of the use of the many different uses, although there are also very different, but because of its role are from the charging and discharging. The following are some of the role of capacitors:
Coupling capacitance function: used in the coupling circuit of the capacitor is called coupling capacitance, in the resistance-capacitance coupled amplifier and other capacitively coupled circuits in the use of such capacitor circuits, play a role in isolating the flow of AC.
Filter capacitance function: used in the filter circuit of the capacitor is called filter capacitor, in the power supply filter and various filter circuits use this capacitor circuit, filter capacitor will be a certain frequency band of signals from the total signal removal.
Decoupling capacitor function, used in the decoupling circuit of the capacitor is called decoupling capacitor, in the multi-stage amplifier DC voltage supply circuit using this capacitor circuit, decoupling capacitor to eliminate the harmful low-frequency crosslinks between each amplifier stage.
High-frequency dissipation capacitance function: used in high-frequency dissipation circuit capacitors called high-frequency dissipation capacitance, in the audio negative feedback amplifier, in order to dissipate the possible high-frequency self-excitation, the use of such capacitor circuits, in order to eliminate amplifiers may appear high-frequency whistling.
Resonant capacitor function: used in the LC resonant circuit capacitor called resonant capacitor, LC parallel and series resonant circuits need this capacitor circuit.
Bypass capacitor function: used in the bypass circuit of the capacitor is called bypass capacitor, the circuit if you need to remove a certain band of signals from the signal, you can use the bypass capacitor circuit, according to remove the signal frequency is different, there is a full-frequency domain (all AC signals) bypass capacitor circuits and high-frequency bypass capacitor circuits.
Neutralisation capacitor function: Capacitors used in neutralisation circuits are called neutralisation capacitors. These neutralising capacitor circuits are used in radio high-frequency and intermediate-frequency amplifiers, and TV high-frequency amplifiers to eliminate self-excitation.
Timing Capacitor Function: Capacitors used in timing circuits are called timing capacitors. Timing capacitor circuits are used in circuits that require time control through capacitor charging and discharging, and the capacitor plays a role in controlling the size of the time constant.
Integral Capacitor Function: The capacitor used in an integral circuit is called an integral capacitor. In the synchronous separation circuit of potential field scanning, this integral capacitor circuit is used to remove the field synchronous signal from the field composite synchronous signal.
Differential capacitance function: the capacitor used in the differential circuit is called differential capacitance. In the trigger circuit in order to get the top trigger signal, the differential capacitor circuit, in order to get the top pulse trigger signal from all kinds of (mainly rectangular pulse) signal.
Compensation Capacitor Function: The capacitor used in the compensation circuit is called compensation capacitor. In the bass compensation circuit of the deck, this low-frequency compensation capacitor circuit is used to enhance the low-frequency signal in the playback signal, and there is also a high-frequency compensation capacitor circuit.
Bootstrap Capacitor Function: The capacitor used in the bootstrap circuit is called a bootstrap capacitor, and the commonly used OTL power amplifier output stage circuits use such bootstrap capacitor circuits to enhance the positive half-period amplitude of the signal in a small amount by way of positive feedback.
Crossover capacitance function: the capacitor in the crossover circuit is called crossover capacitor, in the speaker crossover circuit of the speaker, the use of crossover capacitance circuit, in order to make the high-frequency speakers work in the high-frequency band, mid-frequency speakers work in the mid-frequency band, and low-frequency speakers work in the low-frequency band.
Load capacitance function: It is the effective external capacitance that determines the resonant frequency of the load together with the quartz crystal resonator. The standard values of load capacitance are 16pF, 20pF, 30pF, 50pF and 100pF. The load capacitance can be adjusted according to the specific situation, and by adjusting the load capacitance, the operating frequency of the resonator can be adjusted to the nominal value. Digital multimeter in the capacitance function role there are many kinds, mainly depends on the electrician with a digital multimeter * need to measure what objects.
