This article covers:

1. Definition of parasitic capacitance

2. Sources of parasitic capacitance in circuits

3. Methods for measuring and analyzing parasitic capacitance

4. How to reduce the impact of parasitic capacitance

Definition

Parasitic capacitance is a phenomenon where components in a circuit behave like capacitors even though they are not designed to be capacitors.

Meaning: Originally, there was no capacitor designed in that location, but because there is always mutual capacitance between wiring, it is as if there is a parasitic capacitance between the wiring, so it is called parasitic capacitance, also known as stray capacitance. (Official explanation)

Parasitic capacitance itself is not a capacitor. According to the principle of capacitance, a capacitor generally consists of two plates and an insulating medium. Therefore, parasitic capacitance is unavoidable.

From this, we can infer that it is due to factors such as the structure and materials of electronic components, so parasitic capacitance is unavoidable. At the same time, the presence of parasitic capacitance can affect the performance of the circuit.

Parasitic Capacitance in Circuits

Parasitic capacitance often occurs in circuits and generally comes from the following aspects:

a. Capacitance between components (wiring, pins, etc., between different components) b. Capacitance between components and ground (wiring, pins, etc., between components and ground) c. Capacitance on the PCB (formed between different wires, between wires and ground) d. Other factors (electromagnetic interference, temperature changes, etc.)

In circuits, parasitic capacitance can cause signal attenuation and phase shifts, thereby affecting its performance and stability.

Especially in high-frequency circuits, the effect is more pronounced. In high-frequency circuits, parasitic capacitance can cause signal distortion and increased noise.

Methods for Measuring and Analyzing Parasitic Capacitance:

• Use an LCR meter for measurement;

• Use an oscilloscope and signal generator for measurement;

• Use a frequency response analyzer

(All of the above methods have a certain risk of error and require calibration and error analysis in practical applications.)

How to Reduce Parasitic Capacitance

To reduce the impact of parasitic capacitance, we need to take some measures:

1. Shorten the distance between components as much as possible to reduce the capacitance between components.

2. Shorten the distance between component pins and ground as much as possible to reduce the capacitance between components and ground.

3. Proper PCB layout to effectively reduce the capacitance on the PCB.

4. Use shielding measures to reduce electromagnetic interference.

In addition, we can also use compensation circuits, such as using capacitors and inductors to counteract the effects of parasitic capacitance, and use high-speed caches and other optimization techniques to improve system performance and stability.