PCB ranges from single panel (only one copper layer) to multi-layer board (more than 20 layers at most). The more layers are added, the more complex the PCB is, and the more advanced the power supply tools are. More layers also means more electronic components. The rugged PCB can absolutely hold dozens of electronic components. Secondly, there are 13 kinds of the most common PCB components.
13 most common components
- Integrated circuit
- Switch / relay
Printed circuit board (PCB) components are composed of various complex components, in order to make the PCB work normally, each component must play its own role: the result should be a PCB, which is composed of a series of conductive paths etched on the copper plate, and the mechanical path is used to mechanically support large electronic equipment. The following details about diodes, resistors, capacitors, transistors, switches and inductors.
Diode – redirecting energy
Diode is an electrical equipment that transmits current only in one direction, which is composed of semiconductor materials between two terminals (p-type and n-type semiconductor materials at both ends). When a diode enables current in one direction, it blocks current in the opposite direction. However, due to its composition, the behavior of the diode can be controlled.
The test diode is a bit sensitive to operation. If it is not operated properly, it will cause irreparable damage. It is always best to consult a professional before attempting to test any electrical equipment or related components. When preparing to test the diode, disconnect one end of the diode from the circuit board. Using analog instruments (digital instruments sometimes do not record leaking diodes), identify red and black instrument probes. Connect the black probe to the cathode, the red probe to the anode, and set the meter between 1 and 10 ohm. If the meter does not record any readings, the diode may open. If the meter records two readings, the diode may leak. If the meter records some resistance, the diode is forward biased.
Resistor – control energy
Resistor is one of the key components of PCB, which is a small electronic device with two terminals. These terminals transmit current to generate voltage. To test them, use an ohmmeter. First, the resistor must be isolated so that the test results represent only the resistor and are not affected by other component signals. Digital multimeters are better than analog ones because the results are often more accurate. Using a multimeter with an output value of less than 0.6 V will help to avoid causing unexpected conduction of other surrounding resistors. However, if there are other shunt resistors, the result may still be skewed.
Before testing a resistor, determine the exact reading for a particular resistor. Next, connect the lead of the multimeter to a specific resistance and test it. If the result is too high, it may indicate that the resistance is open or a high value has been obtained. Other circuit components usually result in lower readings, so higher values should be interpreted as possible symptoms of the problem.
Capacitor – energy storage
Circuit board capacitor is an electronic device that stores energy as electrostatic field and consists of insulating materials placed between two conductive plates. In PCB, they can block DC current while allowing indirect current. When a DC voltage is applied to the capacitor, the charge is stored by each conductive plate. Current flows as the capacitor stores energy – when the capacitor is fully charged, the current stops flowing. The type of material used as insulating material (dielectric material) determines the type of capacitor. Common insulator materials include ceramics, polycarbonate and argentite. In PCB, the circuit board itself usually produces a capacitor, which is alternately arranged between the metal conductive area, grounding conductor and powder conductor to form a stable capacitor. Within the PCB, decoupling capacitors can be found, which reduce the excess energy by routing the noise to the capacitors, so as to reduce the impact of noise and other elements on the rest of the circuit board.
Transistors – amplifying energy
Resistor may be the basis of current control, but transistor is the basis of all modern electronic products. In fact, they can be considered building blocks.
Instead of storing, adjusting, or controlling charges on a PCB, transistors amplify them. Bipolar transistors are the most common type of transistors with three regions and three pins in which current flows and is amplified. There are two types of bipolar transistors. NPN and PNP. Both of them are composed of (1) base, (2) collector and (3) emitter, and have p-type region and n-type region.
Foundation: the foundation / foundation of the whole equipment
Emitter: place to release / issue charges
Collector: collect charge carrier
NPN bipolar transistor has a p-type region sandwiched between two n-type regions. In NPN type, small current flows from the base to the emitter. This current then turns on another circuit, which also causes more current to flow from the collector to the emitter, effectively increasing (or amplifying) the released current.
The PNP bipolar transistor has an n-type region sandwiched between two p-type regions. This will reverse the current process of NPN type. A small current starts from the collector and flows to the emitter, triggering a larger current to flow through the base and reach the emitter.
NPN transistors are more commonly used than PNP transistors for many reasons. However, both have their advantages and disadvantages, depending on the project.
Switch – power button
Switch is another well-known PCB module, second only to battery. Many people (not only engineers and amateurs) have bought switches for everyday functions. They are not just printed circuit boards. They appear in kitchens, rooms, remote devices, etc.
Consider the switch / relay as a power button. They basically control the current in the circuit by opening and closing the circuit. Tap the switch to disconnect the circuit, allowing current to flow to the bulb in the room. Again, the circuit is closed. The bulb has cut off the current and turned off the power.
There are at least a dozen different types of switches with different physical structures and appearances. More common are button switches, joysticks and toggle switches. Other examples include box, rocker, micro, slide and rotary switches.
Inductors – increase energy
Inductors (such as resistors and capacitors) are considered as linear passive components of PCB. Like capacitors, inductors are devices that store energy at both ends. However, although capacitors store energy in an electrostatic manner, inductors use magnetic fields.
Also known as coils, chokes and reactors, inductors are usually made up of cores wrapped with insulated wires. The more times the wire is wound on the core (i.e. the number of windings), the greater the magnetic field and energy generated. The winding will amplify the magnetic field, thus expanding the energy stored and the energy capacity of the equipment.
Inductors have a characteristic called inductance, which is basically the ratio of voltage to current change rate. They are usually used to filter or block certain signals, such as radio interference in audio devices.