There are different types of packaging for electronic components. Different types of components have the same shape, but their internal structures and uses are quite different. Complex electronic circuits are also composed of these electronic components. For component identification, you can distinguish by looking at the printed model. For devices that do not have characters on the components, you can also determine them by analyzing the circuit principle or measuring the component parameters with a multimeter. So, what are the components commonly used on the PCB board? In order to help you understand, the following content summary for your reference.
One, resistor
Resistance is one of the most commonly used electronic components on PCB board. It is represented by the letter R, and the unit is ohm ω. It represents the resistance of conductor to current. In the circuit plays the role of shunt, current limiting, partial voltage, bias and so on.
Two, capacitor
The letter C stands for capacitor used to store charge and electrical energy in a circuit. Its main feature is the separation of AC and DC. The resistance OF a capacitor to alternating current is called resistance, belonging to a type of resistance (the other type is called inductive resistance). The resistance is related to the frequency of alternating current and its own capacity. In the circuit, capacitors mainly play the role of coupling, filtering, resonance, bypass, compensation, frequency division and so on.
Three, crystal diode
The crystal diode is represented by the letter D. It is a kind of semiconductor device with nonlinear volt-ampere characteristics, mainly used for unidirectional conduction. The core part is a PN junction, which is widely used in various electronic circuits.
There are many kinds of crystal diodes, according to their materials can be divided into silicon tube and germanium tube; According to its functions, there are: rectification, luminescence, detection, voltage regulation, switching, continuous flow, rotation, Schottky diode and silicon power diode; According to its structure point, it can be divided into contact type and plane type, the former can pass a small current, the latter can pass a large current.
Four, inductor
Inductors are represented by the letter L and are similar in structure to transformers. It is a device that converts electrical energy into magnetic energy and stores it in the circuit. It is mainly used for filtering, oscillation, delay, trap, signal screening, noise filtering, current stabilization and electromagnetic interference suppression.
Another name of inductor: throttle, reactor, dynamic reactor, etc., according to their induction mode: self inductance and mutual inductance. Inductors have the characteristic of direct resistance crossing, that is, to prevent AC current from passing through, so that DC current can pass through smoothly, just the opposite of capacitors.
Five, crystal triode
Triode is called semiconductor triode. It is a semiconductor device that controls electric current. It is the core component of electronic circuit. It is also known as a bipolar transistor. Crystal triode has current amplification function. The essence is that the triode can control the large change of collector current by small change of base current. Its magnification is indicated by the symbol "β".
Triode is made on a semiconductor substrate two transistors very close to PN junction, two PN semiconductor is divided into three parts, the middle part for the base region, two sides for the emission region and the collection region. There are two permutations: PNP and NPN.
Six, transistor field effect
Field effect transistor (FET), short for field effect tube. There are two types: JFET(junction type) and metal-oxide semiconductor Field effect tube (MOS-FET). Field effect tubes, also known as monopolar transistors, are voltage controlled semiconductor devices. This function is used for magnification. Due to the high input impedance of the FET amplifier, the coupling capacitance can be small, so the use of electrolytic capacitors is not necessary.
The field effect tube has a very high input impedance, which is very suitable for impedance conversion. It is usually used for impedance conversion in the input stage of a multistage amplifier, and can be used as variable resistance, constant current source, electronic switch, etc.
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