Application of Glazed Resistors and Capacitors
2025-12-22
On the one hand, resistors can act as full frequency filters, and on the other hand, they can reduce the quality factor Q of the circuit. In energy storage circuits, the larger the Q value of the glazed resistor, the smaller the loss, and the stronger the filtering ability for signals in other frequency bands. Therefore, in frequency selection circuits, a larger Q value is better; On the other hand, the larger the Q value of the glazed resistor, the steeper the characteristic curve in the passband of the power or signal line, which is more likely to cause ringing phenomenon. The signal is prone to distortion after passing through this loop, and the smaller the Q value, the better.
There are four considerations for the application of glazed resistors in high-speed circuit design:
The resistance value of a resistor;
The size of the resistance;
Rated frequency of the resistor;
Accuracy of resistance. The accuracy of the glaze resistor directly determines the accuracy of the output voltage in applications. If a glazed resistor with an accuracy of 5% is selected, the voltage fluctuation range of the output power supply can reach 10%.
The role of capacitors in high-speed circuit design
1. Charge buffer pool: Under normal circumstances, the load of the power supply is dynamic, meaning that the current and power consumption of high-speed devices are constantly changing. The essence of glazed resistors and capacitors is to store and release charges. When the external environment changes, the charge in the capacitor can quickly accumulate or release.
When changes in the external environment drive the increase or decrease of the operating voltage of the device, the glazed resistance capacitor can absorb the changes by accumulating or releasing charges, that is, the changes in the operating voltage of the device are converted into changes in the charges in the capacitor, thereby maintaining the stability of the operating voltage of the device. Therefore, this capacitor can serve as a charging buffer to maintain stable operating voltage of high-speed devices.
2. The important discharge path of high-frequency noise: In high-speed circuits, there are always state transitions, which can generate a large amount of noise and other interference in the circuit. In the power transmission path, these interference leaks need to be placed on a relatively stable grounding plane to avoid affecting the operation of the equipment. At higher frequencies, capacitors exhibit lower impedance, making them an important discharge path for high-frequency noise.
3. Realizing AC coupling: Based on the characteristics of glazed resistor capacitors, capacitors have isolation functions through AC and DC resistors, which can achieve AC coupling and DC coupling isolation.
Analysis of Equivalent Circuit of Capacitor
Capacitors are small circuits composed of glazed resistors, inductors, etc., and are classified into the following concepts:
ESL (Equivalent Series Resistance): The enamel resistance is connected in series with the pin inductance of the capacitor and the equivalent inductance between the two poles of the capacitor, depending on the packaging;
ESR (Equivalent Series Inductance): The pin resistance of a capacitor and the equivalent resistance between the two poles of the capacitor mainly depend on the operating temperature, frequency, and conductor resistance of the capacitor itself;
Leakage (parallel leakage resistance): depends on the leakage characteristics of the capacitor components themselves. Follow Sichuang Electric to learn more about glazed resistors.
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