Basic electronic components play a vital role in today's highly digital age, and despite their apparent simplicity, they are powerful, constituting the basic units of complex electronic systems and the key to realizing the functions of various electronic devices. INFINITECH will analyze, one by one, how these basic electronic components work, their specific applications in circuits, and how multimeters can be used to test the state of these components. In addition, we will briefly cover the basic methods and considerations of welding electronic components, which is a very practical skill for both electronics enthusiasts and professional engineers.

What are basic electronic components

Basic electronic components are the basis of electronic circuits and an indispensable part of electronic equipment. Some common components include: resistors, which are used to limit current or reduce voltage; Capacitors, which store charge and help smooth voltage fluctuations; And inductors, which store magnetic field energy and block high-frequency signals to allow low-frequency ones to pass through. Because of their unidirectional conductivity, diodes are used in circuits for rectification or as light emitting diodes (leds). Transistors can amplify current or be used as switches, and common types are bipolar transistors (BJTs) and field-effect transistors (FETs).

In addition to this, integrated circuits (ICs) integrate many electronic components on a small semiconductor chip to achieve complex circuit functions. Other components such as transformers, relays and switches also play an important role in various electronic devices. Together, these basic components form the building blocks of more complex electronic systems.

What is the purpose of the resistor?

Resistors are mainly used to limit the flow of current in a circuit or to reduce voltage. It can protect the sensitive element by limiting the current, such as limiting the current flowing through the LED in the LED circuit to ensure that it works properly. In addition, the resistor can also generate voltage drop to achieve voltage adjustment or distribution; It can be used to reduce the amplitude of the signal, for example in audio signal processing to reduce the volume; It can also be combined with capacitors or inductors to form a filter circuit to remove noise or unnecessary frequency components in the signal. In the transistor circuit, the resistor is used to set the operating point of the transistor to ensure the stable operation of the transistor; Two resistors in series can form a voltage divider, which is used to generate a reference voltage or reference voltage in the circuit; Special types of resistors, such as thermistors, can be used for temperature detection or temperature compensation circuits.

What is the function of a capacitor?

The main function of a capacitor is to store charge. When a voltage is applied to both ends of a capacitor, it accumulates opposite charges between the two conductors. Capacitors have many uses in electronic circuits, including filtering, coupling and bypass. For example, it can be used to smooth out voltage fluctuations in a DC power supply, removing ripple voltage from the power supply and making the output more stable. During signal transmission, capacitors can be used to connect two circuits while blocking the DC component from passing through and allowing only AC signals to pass through. In addition, capacitors can also be used to bypass certain parts of the circuit, allowing AC signals to bypass unwanted parts and reach their destination directly.

In addition to the above functions, capacitors are also used in applications such as energy storage, timing, decoupling, phase shifting, and oscillating circuits. In applications where energy needs to be released quickly, such as flash light circuits, capacitors can store energy and release it when needed. When used in combination with resistors, capacitors can form RC (resistance-capacitance) circuits that are used to generate delay or timing signals. In integrated circuits and other electronic modules, capacitors are used to decouple transient voltage changes on the power line to ensure the stability of the power supply. In AC circuits, capacitors can be used to change the phase of the signal, which is very important for the design of some circuits. In addition, capacitors combined with inductors can form LC oscillating circuits for generating stable AC signals.

The unit of the capacitor is farad (F), but in practice the capacitance value used is usually much less than 1 farad, and the common units are micromethod (μF), nanomethod (nF) and picomethod (pF). The choice of capacitors depends on the specific application required, including factors such as the required capacitance, withstand voltage value and operating frequency.

What are the characteristics of diodes?

The characteristic of the diode is one-way conductivity. This means that the current can only flow through the diode in one direction (forward) and not in the other direction. When the diode is forward-biased, that is, the anode voltage is higher than the cathode voltage, it allows current to pass through; In reverse bias, where the anode voltage is lower than the cathode voltage, it prevents the current from passing through unless the voltage exceeds a certain threshold (breakdown voltage). This property allows diodes to have a variety of applications in electronic circuits, such as rectification, which converts alternating current to direct current; Protect the circuit to prevent damage to the circuit caused by reverse current or voltage spikes; And clipping, which limits the amplitude of the signal to not exceeding a certain voltage level.

In addition to the above applications, diodes are also widely used in luminescence, voltage regulation and photoelectric effect. Light-emitting diodes (leds) emit light when forward-biased and are widely used in indicator, display and lighting fields. Voltage regulator diodes (Zener diodes) can maintain a stable voltage over a certain current range when reverse-biased, so they are often used in voltage regulator circuits. Photodiodes use the current generated by light irradiation to work, and are commonly used in the field of light detection and optical communication. These characteristics make diodes an indispensable component in electronic circuits.

How do transistors work?

Transistors, which amplify signals or act as switches, are central components in modern electronic devices. There are two main types of transistors: bipolar transistors (BJT) and field-effect transistors (FET), and INFINITECH explains how each works.

Bipolar transistor (BJT)

A bipolar transistor (BJT) is a type of current-controlled device that operates based on the flow of charge carriers (electrons and holes). There are two types of BJT: NPN type and PNP type.

NPN type transistor: When the base is forward-biased relative to the emitter, a small number of carriers (holes) injected by the base enter the collector region. If the collector is also positively biased with respect to the emitter, these holes will be attracted to the collector, resulting in a collector current. The ratio of the collector current to the base current is called the gain (β), and this allows the transistor to amplify the current.

PNP type transistor :PNP type transistor works similar to NPN type, but the current direction is opposite. When the base is forward-biased relative to the emitter, a small number of carriers (electrons) injected by the base enter the collector region. If the collector is also positively biased with respect to the emitter, these electrons will be attracted to the collector, resulting in a collector current.

Field-effect transistor (FET)

A field-effect transistor (FET) is a voltage-controlled device whose operation is based on the grid voltage controlling the electric field in the channel region.

Enhanced MOSFETs: When enough voltage is applied to the gate relative to the source, enough electric field is generated in the channel to form a conductive path between the source and drain. The drain current changes as the gate voltage changes, which allows the MOSFETs to be used as amplifiers or switches.

Depletion MOSFETs: This type of MOSFETs already form a conductive channel when there is no gate voltage. Applying a negative gate voltage can close the channel, while a positive gate voltage can increase the conductivity of the channel.

Apply

Transistors can amplify the electrical signal enough to drive a load or further processing.

Transistors can be used as efficient electronic switches to control the switching of current.

In digital electronics, transistors are used to build basic logic gates, such as AND gates, OR gates, etc.

Transistors can be used to build oscillating circuits that produce stable AC signals.

Transistors can be used in voltage regulator circuits to ensure that the output voltage is stable.

What is Integrated Circuit (IC)?

An integrated circuit (IC) is a tiny electronic device that integrates a large number of electronic components on a small semiconductor chip. This integration technology has several notable features: Integrated circuits have a high degree of integration and are able to integrate thousands of electronic components in a very small space, significantly reducing the size and weight of electronic devices. In addition, integrated circuits usually have low power consumption characteristics, suitable for mobile devices and other battery-powered applications. Due to the tight connection between the components, integrated circuits are able to provide higher performance, fast signal transmission speed and low latency. The manufacturing process of integrated circuits makes them more reliable than the components, the failure rate is low, and mass production can significantly reduce costs and improve economic efficiency.

Integrated circuits are widely used in many fields. In computer science, the central processing unit (CPU), graphics processing unit (GPU), and other computing chips are highly integrated integrated circuits. In terms of memory, dynamic random access memory (DRAM), static random access memory (SRAM) and flash memory are also common integrated circuits. In the field of communication, integrated circuits for communication such as wireless communication chips, modems and RF transceivers are widely used in mobile phones, wireless routers and other devices. In addition, integrated circuits also play an important role in many fields such as consumer electronics, automotive electronics, medical equipment, and industrial control. Whether it's a digital camera, a TV or a pacemaker, integrated circuits are an indispensable and critical component. With the continuous progress of technology, integrated circuits will continue to develop towards higher integration, lower power consumption and stronger functions.

How do I test electronic components with a multimeter?

Multimeter is a kind of multifunctional electronic measuring instrument, which can be used to measure voltage, current, resistance and other electrical parameters. Knowing how to test different electronic components with a multimeter is a very useful skill for electronics enthusiasts and engineers. Here are some ways that INFINITECH has put together to test common electronic components using a multimeter:

Test the resistor

• Select the right mode: Set the multimeter to Ohm (Ω) mode.

• Select the right range: Select the right range according to the expected resistance value.

• Test resistance: Disconnect the circuit where the resistor is located to avoid other components affecting the measurement result. Use the test probe of a multimeter to touch both ends of the resistor. See if the reading is close to the nominal value.

Test capacitor

• Choose the right mode: Most multimeters cannot directly measure the capacitance value of the capacitor, but it can be judged by indirect methods.

• Discharge: Make sure the capacitor is fully discharged before testing.

• Test capacitors: Set the multimeter to resistance mode. Touch the test probe to both ends of the capacitor and observe the reading change. A good capacitor should first display a low resistance and then gradually rise to infinity.

Test diode

• Choose the right mode: Set the multimeter to diode test mode (usually with a diode symbol).

• Test diode: Forward test: The red probe (usually positive) touches the anode of the diode, and the black probe (usually negative) touches the cathode. Reverse test: The black probe touches the anode and the red probe touches the cathode. Normally, the forward test should show a low voltage drop (usually about 0.6V to 0.7V for silicon diodes and 0.2V to 0.3V for germanium diodes), and the reverse test should show infinity or overload symbols.

Test transistor

• Choose the right mode: Set the multimeter to hFE mode (to test the gain of the transistor) or resistance mode.

• Test transistor: For NPN or PNP transistors, the red probe touches the base and the black probe touches the emitter. Observing the reading, a good transistor should display a reasonable gain value. For field-effect transistors (FETs), the test method may be slightly different, usually requiring the probe to touch the gate, source, and drain, and paying attention to the electrostatic sensitivity of the gate.

Test integrated circuit

• Select the right mode: Set the multimeter to voltage mode.

• Test the integrated circuit: Disconnect the circuit power supply to avoid short circuit. Use a multimeter to measure the voltage between individual pins and compare it with the recommended value in the data book. Note: Testing of integrated circuits often requires more expertise, as measuring voltage alone may not be enough to determine the state of an integrated circuit.

Matters needing attention

• Before testing any component, make sure the circuit is powered off.

• Use the correct range to avoid damaging the multimeter.

• Calibrate the multimeter before testing to ensure accuracy.

• Follow safety guidelines to avoid the risk of electric shock.

How to weld electronic components?

Prepare tools:

Welding iron: Select a suitable temperature controlled welding iron.

Solder wire: Select solder wire suitable for electronic components.

Cleaning sponge: Used to clean welded iron ends.

Diagonal pliers or tweezers: Used to hold or clamp small components.

Welding AIDS (such as flux) : Help the solder flow better and form good solder joints.

Prepare the workspace:

Make sure your workbench is secure and clean.

Use anti-static pads to protect sensitive components from electrostatic damage.

Prepare the circuit board and components to be welded.

Heating welding iron:

Set the appropriate temperature according to the type of welding iron used.

Use a cleaning sponge to keep the welded iron head clean.

Preparation before welding:

If needed, apply a small amount of flux to the solder joints.

Place the components correctly on the board and make sure the pins are aligned with the appropriate holes.

Welding process:

Touch the heated welded iron head to the solder joint and component pin and preheat it for a few seconds.

At the same time, touch the solder wire to the solder joint and gently remove the solder wire when the solder begins to melt.

After the solder has cooled and solidified, remove the solder iron.

Check the solder joints:

Ensure that solder joints are smooth, crack-free and free of bridging.

Check whether there is any welding or short circuit.

Clean up workspace:

After welding, clean the working area and store the tools properly.

Through the above steps, you can safely and effectively complete the welding of electronic components. Practical experience and patience are the keys to improving your welding skills.