Capacitance experiment

Experiment 19 Observing capacitance characteristics

【Purpose requirement】

1. Observe the charging and discharging phenomena of the capacitor and understand the characteristics of the capacitor;

2. Determine the capacitance based on the frequency characteristics of the capacitive reactance.

【Experimental Principle】

1. Capacitor

The capacitor is one of the commonly used electronic components. The commonly used capacitor uses two layers of metal foil (membrane) as the polar plate. There is a layer of insulating material in the middle of the polar plate as a medium. The voltage ratio is the capacitance.

Capacitors are divided into fixed capacitance and variable capacitance. Its main parameters are: capacitance value and rated working voltage. Due to the charging and discharging characteristics of the capacitor and the ability of the capacitor to block DC and AC, it is often used in filter circuits, timing circuits, sawtooth wave generator circuits, differential integration and other circuits.

2. Charging and discharging characteristics of RC circuit

3. Use an oscilloscope to observe the changes in the voltage on the capacitor and the resistance on the capacitor during the charging and discharging of the RC circuit

4. Relationship between capacitance impedance and frequency

【Experiment content】

1. Use the DC voltage range of the digital multimeter to observe the charging and discharging of the capacitor in the RC circuit.

2. Observe the charging and discharging phenomenon of the RC circuit with an oscilloscope.

3. Determine the capacitance based on the relationship between the capacitive reactance and frequency.

【Instruments】

Serial number

equipment name

Model / Specification

Unit price (yuan)

Remarks

1

4 and a half digital multimeter

DY2106

290

Compatible with other experiments

2

DC power supply

DH-VC1

900

3

Signal generator

DH-WG1

900

4

Circuit design experiment device

DH-SJ1

2200

5

capacitance

Two, one is an electrolytic capacitor, the capacitance value is about tens of microfarads; the other is about 0.06 microfarads

6

Dual Trace Oscilloscope

MOS620CH / 20MHz

1800

Can choose one

Digital storage oscilloscope

TH1022A / 25MHz

2450