What are the components commonly used on circuit boards? What do they do?

In the circuit board, all kinds of electronic components have their own role, we will explore the following. Although the circuit does not say how proficient, but we must at least read the circuit, know the role, the following summary of the role of some electronic components.

1. Resistors: resistors are mainly used in circuits to regulate and stabilize current and voltage, and can be used as shunts, voltage dividers or circuits for load matching. The circuit can also be used to amplify the negative or positive feedback of the circuit, voltage and current conversion, voltage or current protection components when the input is overloaded, as well as RC circuits for oscillation, filtering, bypass, differentiation, integration, time constant components, etc.

2. capacitor: generally the role of the filter, the smaller the frequency of the filter, generally 103, 104 capacitors, the author made the project is right, using 104 capacitors, in the chip, no artificial elimination of vibration (103 represents, 10^3pf).
3. Triode: this is a relatively common component, in the digital circuit, generally used in the role of the switch. It is the use of transistor conduction and cut-off characteristics to switch the circuit, the digital tube used in the author's project is to use the transistor to control the digital tube out, bright, if the chip directly with the IO port output high and low, to control the digital tube output, then when the output is low, it will be very large, the chip will burn out.

4. inductor: electromagnetic relations believe that we all know very well, the role of the inductor is that when the circuit begins, everything is still unstable, if the inductor has current through, will certainly produce the opposite direction of the current induction current (Faraday's law of electromagnetic induction), wait until the circuit runs for a period of time, everything is stable, the current does not have any changes, electromagnetic induction will not occur suddenly (Faraday Law of electromagnetic induction), so that after the circuit has been running for a while, everything is stable, the current does not produce any current, and therefore no sudden changes occur, thus ensuring the safe operation of the circuit, and then slowly tends to calm down.

5. Magnetic beads: Magnetic beads have high resistance and permeability, which is equivalent to resistance and inductance in series, but the resistance and inductance values change with frequency. Its high frequency filtering performance is better than that of ordinary inductors, and it is resistive at high frequencies, so it can maintain a high impedance over a fairly wide range of frequencies, thus improving the effect of FM filtering, which has been used on Ethernet chips.