Capacitance function of the multimeter
When electricians use digital multimeters, according to the function of capacitance in the circuit, the basic functions of capacitors are charging and discharging. However, many circuit phenomena extended from this basic charging and discharging function make capacitors have various uses, such as in electric motors. In electronic circuits, electricians use it to produce phase shifts; in photographic flashlights, they use it to produce high-energy instantaneous discharges, etc.; and in electronic circuits, capacitors have many uses with different properties. These many different uses, although they are also completely different. The difference is that their functions come from charging and discharging. Here are some functions of capacitors:
Coupling capacitor function: The capacitor used in coupling circuits is called coupling capacitor. This capacitor circuit is widely used in resistor-capacitor coupling amplifiers and other capacitor coupling circuits to isolate DC and AC.
Filter capacitor function: The capacitor used in the filter circuit is called a filter capacitor. This capacitor circuit is used in power supply filtering and various filter circuits. The filter capacitor removes signals within a certain frequency band from the total signal.
The function of decoupling capacitors. The capacitors used in decoupling circuits are called decoupling capacitors. This capacitor circuit is used in the DC voltage supply circuit of multi-stage amplifiers. The decoupling capacitors eliminate harmful low-frequency cross-connections between each stage of amplifiers. .
The function of high-frequency vibration-damping capacitor: The capacitor used in the high-frequency vibration-damping circuit is called the high-frequency vibration-damping capacitor. In the audio negative feedback amplifier, in order to dampen the possible high-frequency self-excitation, this capacitor circuit is used. to eliminate possible high-frequency feedback from the amplifier.
Resonant capacitor function: The capacitor used in the LC resonant circuit is called a resonant capacitor. This capacitor circuit is required in both LC parallel and series resonant circuits.
Bypass capacitor function: The capacitor used in the bypass circuit is called a bypass capacitor. If you need to remove a signal in a certain frequency band from the signal in the circuit, you can use a bypass capacitor circuit. Depending on the frequency of the removed signal, there are all types of bypass capacitors. Frequency domain (all AC signals) bypass capacitor circuits and high frequency bypass capacitor circuits.
Neutralizing capacitor function: The capacitor used in the neutralizing circuit is called neutralizing capacitor. In radio high-frequency and intermediate-frequency amplifiers and television high-frequency amplifiers, this neutralizing capacitor circuit is used to eliminate self-excitation.
Timing capacitor function: The capacitor used in the timing circuit is called a timing capacitor. Timing capacitor circuits are used in circuits that require time control through capacitor charging and discharging. The capacitor plays a role in controlling the time constant.
Integrating capacitor function: The capacitor used in the integrating circuit is called the integrating capacitor. In the synchronization separation circuit of electric potential field scanning, this integrating capacitor circuit can be used to extract the field synchronization signal from the field composite synchronization signal.
Differential capacitor function: The capacitor used in the differential circuit is called a differential capacitor. In order to obtain the peak trigger signal in the flip-flop circuit, this differential capacitance circuit is used to obtain the peak pulse trigger signal from various types of (mainly rectangular pulse) signals.
Compensation capacitor function: The capacitor used in the compensation circuit is called the 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. In addition, there are high-frequency Compensation capacitor circuit.
Bootstrap capacitor function: The capacitor used in the bootstrap circuit is called a bootstrap capacitor. Commonly used OTL power amplifier output stage circuits use this bootstrap capacitor circuit to slightly increase the positive half-cycle amplitude of the signal through positive feedback.
The function of the frequency dividing capacitor: The capacitor in the frequency dividing circuit is called the frequency dividing capacitor. In the speaker frequency dividing circuit of the speaker, the frequency dividing capacitor circuit is used to make the tweeter work in the high frequency band and the mid-frequency speaker work in the mid-frequency band. , the subwoofer works in the low frequency band.
Load capacitance function: refers to the effective external capacitance that determines the load resonant frequency together with the quartz crystal resonator. Commonly used standard values for load capacitance are 16pF, 20pF, 30pF, 50pF and 100pF. The load capacitance can be adjusted appropriately according to the specific situation. Through adjustment, the operating frequency of the resonator can generally be adjusted to the nominal value. The capacitance function in a digital multimeter has many functions, mainly depending on what objects an electrician needs to measure when using a digital multimeter.
