"Electronic engineer must have basic knowledge (1)
The operational amplifier has been widely used in analog circuits and digital circuits through a simple peripheral component. The operational amplifier has a good model, there are several differences in detailed performance parameters, but the principle and application methods are the same.
The op amp usually has two inputs, ie forward inputs and reverse inputs, and only one output. Some operational amplifiers In addition to two inputs and an output, there are several compensation pins that improve performance.
The resistance of the photosensitive resistor changes with the change of light of light. Therefore, it can be used to make smart curtains, street lights automatic switches, camera shutter time automatic regulators.
The reed tube is an electronic component capable of controlling the circuit through a magnetic field. The inside of the reed tube is composed of a soft magnetic metal **. In the case of a magnetic field, the metal ** can aggregate the magnetic line and the action of the force, thereby achieving the on or off.
Electronic engineer must-have basic knowledge (2)
The capacitance is used to use three words: "charge and discharge." Don't underestimate these three words, because these three words, capacitors can pass alternating electricity, isolated from high frequency AC, hinder low frequency alternating current.
The function of the capacitor If the role is used in eight words: "The accepted straight, the high level is low." These eight words are based on the three words of "charge and discharge", do not understand, let alone .
It is possible to first select filter capacitance according to the magnitude and post-secondary (circuit or product) of the DC power output current, usually, in the case, each of the ampere currents correspond to 1000UF-4700UF is relatively appropriate.
Electronic engineer must have basic knowledge (3)
The effect of inductance uses four words: "Electromagnetic conversion." Don't underestimate these four words, because these four words, inductors can separate alternating current, via DC AC electricity, hinder high frequency AC electricity. The effect of inductance is used to use eight words: "Space is separated, and the high level is high." These eight words are based on the three words of "electromagnetic conversion".
Inductance is the dead opposite of the capacitor. In addition, inductors have such a feature: current and magnetic fields must exist at the same time. The current should disappear, the magnetic field will disappear; the magnetic field will disappear, the current will disappear; the magnetic field will change, the current positive and negative poles will also change.
The current and magnetic fields in the inductance have been "playing civil war", currently thinks, and the magnetic field is not changed; the magnetic field wants to change, the current is not allowed to change. However, due to external reasons, current and magnetic fields may have to change. Plus the voltage to the inductor coil, the current can make a change from zero, but the magnetic field will oppose, so the current has slowly become large; the inductance removes the voltage, the current is going to zero, but the magnetic field should be opposed, but the current circuit Nothing, the current has been forced to zero, the magnetic field will be angry, immediately generate a high voltage at both ends of the inductor, attempt to generate current and maintain the current constant. This voltage is very high, or even damage the electronic component, this is the self-induction of the coil.
A changed magnetic field is added to an inductor wire, as long as the coil has a closed loop, the coil will generate a current. If there is no loop, a voltage will be generated on both ends of the coil. The purpose of generating a voltage is to attempt to generate current. When two or more tips are shared (aggregated magnetic lines) or sharing a magnetic field, the current and magnetic fields between the coils will affect each other, which is the mutual inductance of the current.
Everyone can see that the inductance is actually a wire. The resistance to the direct current is small, and it can even be ignored. Inductance to AC electricity exhibits a large resistance.
The inductance is in series, in parallel, because the inductance is actually a wire is distributed at a certain position route, so the inductance is connected in series, and the position of the inductance is related (mainly the mutual effect of the magnetic field), if not Considering the effect of magnetic field and distributed capacitance, the wire resistance (Q value), etc., is equivalent to the series, parallel effects of the resistance.
The higher the frequency of AC, the greater the hindrance of inductance. The lower the frequency of the AC, the smaller the inductance.
When the inductance and filled capacitance are in parallel, the capacitor discharge will give inductance, inductance generate magnetic field, and the magnetic field will maintain the current. The current will be charged back to the capacitor. After the reverse charging, it will discharge, and the weighted start ... If there is no loss, Or can supplement this loss in a timely, it will generate stable oscillations.
Electronic engineer must have basic knowledge (4)
The coupling is the meaning of the transfer signal, and the photocoupler is naturally the element of the transmitting electrical signal, which is generally referred to as a light-emitting portion and the receiving portion corresponding to and fabricating an electronic component. Usually four valid pins (ie, the four pin access circuits work) are a group.
The advantage of photocouplers is to easily achieve power isolation, which is most common in the initial secondary isolation of the switching power supply in the market. In addition, in the computer peripheral communication, there are more applications, and multiple sets of photocouplers (at least four pins per group) can be integrated in one element.
Piezoelectric ceramic sheets can perform excellent vibration detectors, which is an electroacoustic device. When the audio voltage is added, the sound can be heard; when the vibration (generating mechanical variable), a weak voltage can be induced.
When welding, appropriate adjustments are welded, solder, solder wire (with flux), let three points together, fully contact, when the welding is already proper solder and flux, the solder wire should be removed. . Welding processes are usually appropriate in 2-3 seconds.
Flux: Rufu water is often used in the factory. Everyone can amaten homemade, use industrial alcohol (medical alcohol than expensive, no need) melting loosening. Pay attention to: Don't match too much once, the concentration can be flexible.
Electronic engineer must have basic knowledge (5)
The effects and functions of the diode use four words: "One-way electrical conductivity." Diode is often used to rectify, detect, regulate, clamp, protective circuits.
A rectifier diode is string in the power supply loop in Walkman. When the DC power is reversed, the current does not generate the current, and it will not damage the Walkman.
Diode (silicon data) plus a forward voltage lower than 0.6V, the diode is substantially not generated (the reverse is more unable to generate current), this voltage is called dead zone voltage, threshold voltage, threshold voltage, conduct Voltage, etc.
The effects and functions of the triode are completed because four words are completed: "The resistance varies." Due to the variation of the resistance value such as the triode, the triode can be used to design a switching circuit, an amplifying circuit, and a oscillating circuit.
The collector current of the triode is equal to the base current by magnification, when the base current is large to a certain level, the current collector is not possible to increase due to various reasons, and the current collector voltage has been equal to or close to the emitter The voltage is equivalent to the resistance value to become 0 ohm.
A confidential trick of the confident triode: transmitting the nodule, the assembly is reflarmed.
The triode is current controlled device, field effect tube is a voltage controlled device. Field effect tube performance is excellent, but in discrete components, low power supply voltage is poor than the triode.
The field effect tube is a voltage controlled device, which is easily damaged, so there are many protective diodes in the field effect tube.
Controllable silicon is actually a high-speed, no electronic switch without mechanical contacts, this switch needs to be grasped with a small current. This switch has a self-locking function, i.e., the withdrawal of the hand is still maintained, and once it is closed, it can maintain an off state.
Electronic engineer must-have basic knowledge (six)
Electrical resistance usually uses color loop labeling. The color label is the use of brown, red, orange, yellow, green, blue, purple, gray, white, black ten colors represent 1234567890 ten arabic figures, gold, silver two colors represent the magnification of 0.1, 0.01 or error 5%, 10 %. Realt and multi-color ring resistance with color samples in the kit
Common four-color ring to read three effective numbers, one or two represents a number of valids, the third represents the magnification. Example: Yellow purple gold, three effective numbers are 472, indicating 47 multiplied by 102 (or two 0) equal to 4700, ie 4.7K ohms;, as: brown black gold, three effective numbers are 100, indicating 10 multiplication Take 100 (or 0 0) equal to 10, ie 10 ohms.
In the experimental process, if there is no unidirectional conductive characteristic (or unspeakable) between the base and other pins of the triode, the triode is bad; in addition, even if the one-way conductive characteristics are normal, However, it cannot be affected by base control or unstable, and it means that the triode is bad, or the performance is poor.
The thyristor is a suitable trigger current, and the thyristor can be turned on from the disconnected state. At this time, we cancel the control pole trigger current, but the thyristic silicon still maintains the on state. . If the current flowing through the thyristor becomes smaller, the controllable silicon is turned off until the next trigger is triggered until it is triggered next time.
Electronic engineer must have basics (seven)
As early as more than two thousand years ago, people found electrical phenomena and magnetic phenomenon. my country has invented Sidan during the Warring States Period (475 BC). The truly understanding and extensive application of electricity and magnetism has also been only more than 100 years. Under the promotion of the wave of the first industrial revolution, many scientists have been in detail and meticulous research on electricity and magnetic phenomenon, which has made significant progress. It is found that the charged object is homogeneous, isotropic, similar to magnetic phenomena.
In 1785, the French physicist Coulomb put forward the "Coulomb Law" known as the future generations of "Coulomb Law" called the future generations, so that the electromagnetic phenomenon has been unified.
In 1800, Italy physicist volts developed chemical batteries, and used artificial methods to obtain continuous batteries, and created primary conditions for future generations of electrical and magnetic relationships.
In 1822, based on the average work of the British Faraday, I proposed the electromagnetic induction law, proved that "magnet" can generate "electricity", which lays a foundation for generators and electric motors.
In 1837, the American painter Morse designed a relatively practical and utilized electricity report on the present, and then established the world's first telegraph line between Washington and Baltimore.
In 1876, Bell in the United States invented the phone and realized the earliest simulation communication of humanity. On the basis of summarizing the previous people, Maxwell proposed a complete "electromagnetic theory" and showed four differential equations. This is called the "Maxwell Equation Group" called by the future. Maxwell draws the conclusion: the electric charge can produce electromagnetic radiation, forming an electromagnetic wave that is gradually spread, invisible. Although he did not raise the term "radio", his electromagnetic theory has already told people that "electricity" is able to "wireless".
Electronic engineer must-have basic knowledge (eight)
Beginology electronic knowledge, please first put "electricity" as "water", "circuit" is equal to "waterway"; then understand several commonly used nouns, comparison with several common electronic components and its functions; finally do a few experiment.
Any electronic product is composed of electronic components, and learning electronic technology will learn electronic components.
The combination of electronic components has become an electronic circuit, which is also a basic knowledge. With electronic components, electronic circuit knowledge, electronic tools will be used, you should do more products.
Learning electrons can benefit from self-loading audio and amplifiers. Appreciating music itself is a beautiful enjoyment, but you can enjoy a new realm with your own results.
I understand that I understand that I don't understand that I don't understand that I don't understand that I don't know how to learn a computer. Computers who understand electronic friends are outside the computer, and friends who don't understand electronics have learned from the computer outside the computer.
Which is "field"? Sports field often refers to a range of exercise, and the electric field is a range of electricity generating force, and the magnetic field is a range of magnetic generating force, and other classes.
The conductor is easier to pass. Insulator, electricity is more difficult to pass. The conductors and insulators have no significant intermissions, conductors and insulators are opposite two objects that are substantially better than those of the conductive capacity.
There are some objects that exhibit different conductive conditions in common different physical conditions (temperature, electric field, magnetic field, light, doping, etc.). We call such objects for semiconductors.
With conductors, insulators, and semiconductors, we can produce a wide variety of electronic components, we can easily and easily detect and use electricity.
The switch is actually a short-circuitry and an open counter, which is a resistor that transforms from zero ohm and infinity two resistance, which is the same as the effect and principles of the water switch.
At any time, as long as there is current flow, there must be a closed pathway. This path is current loop. When the inside of the power supply is not considered, the current must be from the positive current to the negative electrode.
The power supply is equivalent to a special electronic component, and there is a closed path to generate current. No conductors and other electronic components are connected to closing paths.
If you don't have a circuit, you must have no current, there is a circuit that there must be loop. (The AC current does not require a physical pathway, vacuum, and air can also form a current loop.)
There is a water difference in two different water level lines, which is water pressure. If there is a water pipe between the water pressure, the water will flow and the water flow will be resistant. The wet the water pipe, the greater the resistance, the smaller the water flow; the higher the water pressure, the greater the water flow. The voltage refers to the potential difference between the two objects, that is, the voltage. If there is a conductive path between the voltage, the current will generate a current. The larger the resistance, the smaller the current; the higher the voltage, the greater the current.
Water pressure, water flow, water resistance. The direction of water flow is from a high place to the lower level (not the pumping machine); the metaphor of corresponding electricity: voltage, current, resistance. The direction of current is from the positive current to the negative electrode (not the power source).
The water level difference between the two water level is equal to the water pressure; the potential difference between the two electrodes is equal to the voltage. High water levels are equivalent to positive electrodes, and low water levels are equivalent to negative electrodes.
Electronic engineer must have basic knowledge (Nine)
Electrical components such as resistors, capacitors, diodes have two pins, which must connect their pins in accordance with certain regularities.
The triode corresponds to a resistor that can be controlled by a resistance, and the two pins of the collector and emitter of the triode are effectively formed into a resistor, and the base is controlled.
All electronic components have two basic connection methods. Parallel: The voltage across the parallel circuit is equal. Series: The current in the series circuit is equal.
In parallel and in series, it is the most basic circuit connection, regardless of the multi-complex circuitry can be broken down into substantially parallel and in series, all electronic components are also due to parallel and series picks to form current circuits.
The value of the resistor is, the smaller, which is equivalent to the water pipe, the path is width, the resistance of the water flow is small; the resistance of the resistance is, the larger the strings, which corresponds to the growth of the water pipe, the pathway is long, and the resistance of the path is long. Big.
When the voltage is measured, it must be parallel to the two ends that need to be tested, and the voltage meter is presented in the abpacted current to make a pointer to deflect. In general, the internal resistance of the voltmeter can be negligible.
When measuring current, it must be connected in series in series in need to test (need to be disconnected first).The current table will hinder the current small hindrance. Generally, the internal resistance of the current table is smaller.
Electronic engineer must-have basic knowledge (10)
The power supply is a device that maintains the voltage between two test points, which can be a main electricity, which can be a battery, which can be a coil, which can be a capacitor.
The voltage of the battery provides electrical energy is fixed for a long time, we call DC. The rated voltage of the common dry battery is 1.5V.
The electric energy supplied by the market is alternately converted at Alternating current, positive and negative electrode. That is because the generator coil is a relative movement in the week, and the current replacement can be emitted.
The AC is not a positive and negative point, the zero line and the fire line in the city electricity are the same as the performance of the positive and negative polarity, the low voltage, etc., is completely symmetrical.
The electric voltage of the city is 220V50Hz means that the effective voltage is 220V, and the positive negative is 50 times per second. Pay attention to: How much HZ will change how many times.
It is recommended that beginners use DC electronics using DC electricity below 12V, which is low, and the voltage is relatively low. In case there is a plug-in and wrong electronic components, the possibility of burnback components is also small. The lower the voltage, the safer (less damaged electronic components).
Electronic engineer must have basic knowledge (11)
In several large electronic systems, there is often a very thick wire access to the earth. However, it is not true that the grounding of electronic technology is not really required to receive the land.
The ground or groundline that is often mentioned in electronic technology is often not related to the relationship between the earth. The ground wire in the electronic circuit is part of the current circuit, alternating current, or various electrical signals shared.
It is said that there is a small altitude of a mountain, that is, the sea level is a public reference point. It is necessary to find a reference point equivalent to the sea level, which is to find a reference point equivalent to the sea level, which is the ground line in the electronic circuit diagram.
In most cases, the power supply negative is a variety of signals shared a total of a total current loop, usually as a ground wire in the negative electrode of the power source. At this time, if a component's foot is connected to the power supply negative, then the element is grounded.
The ground is a voltage reference point we assume. In a more complex circuit, there may be multiple sets of power supplies, and it may also choose multiple reference points, then there may be multiple places, which are not necessarily connected.
Electronic engineer must-have basic knowledge (12)
Coupled, bypass, and decoupling three words are transmitted signals, which gives signals. The coupling is transmitted, bypass between the front and rear stages, refers to the need to provide signal paths between the ground (internally).
Providing a signal path is also constituent a current loop. There is no current in no current loop, and any circuit analysis is analyzed on current loop.
The equivalent circuit diagram is the same circuit diagram. When we analyze the circuit diagram, we need to simplify the original complicated circuit diagram, which helps to express your ideas and simplify the problem.
The equivalent circuit diagram is omitted under a certain condition, and several electronic components that have nothing affected. Under certain conditions: When analyzing DC, the capacitance will be opened; when analyzing the communication, the capacitance will be a road. Inductance and capacitance are just the opposite.
Capacitors and inductors have different obstacles to different frequencies of alternating current (AC power of DC electricity as 0Hz), under certain conditions, and can be treated as a resistance, and the impedance value can be calculated.
Feedback in life refers to the results of something, and then decide something. For example, the customer feedback TV power consumption is high, and the manufacturer is improved. Feedback in electronic technology is to take out the signal of the output and sent to the input.
The positive feedback refers to the output signal, if the output signal is large, then make the output signal change the output signal; if the output signal is smaller, the output signal is changed to the input signal.
The negative feedback is just the opposite. If the output signal is made large, it is fed back to the input, which makes the output signal becomes smaller; if the output signal is smaller, it is fed back to the input, allowing the output signal to become larger.
Positive feedback is usually used to generate an oscillation signal, and negative feedback is often used to stabilize the DC operating point. In special cases (enlargement is sufficient), positive feedback can not oscillate, negative feedback, but oscillate.
The positive temperature coefficient thermistor means that the resistance increases with the temperature rise, and the negative temperature coefficient means that the resistance is reduced as the temperature increases. A bit icon is positive and negative feedback, and the resistance value is determined by entering the temperature signal.
Electronic engineer must have basic knowledge (13)
In the electronic circuit, the positive and negative voltage of the specified range boundary represents the two-value relative to the daily life, and these positive and negative voltages are high and low. The input and output of the digital circuit are high and low, and the digital circuit is capable of logic judgment based on several two-value relationships to obtain new binary results; binary is 0 and 1 number to represent all quantities. .
The digital circuit is a circuit or circuitry specifically used to use these digital signals. Learning Digital Circuits Recommendation first understands the number of binarys.
The binary number uses 0 and 1 to represent the binary (low level and high level) in the digital circuit, replace all signals with 0 and 1.
The analog signal is a signal that changes between the positive and negative voltages, which should avoid changing to the highest value and minimum value of the positive and negative voltage, otherwise, the signal may distract
D / A (digital / model), A / D (model / number) converter is a common way to combine digital circuits and analog circuits.
Electronic engineer must have basic knowledge (14)
High frequency circuits are very sensitive to small capacitance and inductance. Any wire, and the wires can be equivalent to inductance and capacitance, i.e., distribution inductance and distribution capacitance.
Working in high-frequency state, the pin is short, and the installation distance has a great impact on the performance of the circuit.
When you do a few high-frequency circuits (Example FM wireless microphones, FM radio), remember, remember that the connection should be as short as possible, and components should be close to the circuit board as possible.
Electronic engineer must have basic knowledge (fifteen)
The combination of each electronic component or electronic component and the symbol of their connection relationship is the circuit schematic. As long as you remember the symbols and drawing rules of various electronic components, you will look at the circuit schematic.
The drawings with good habits and rich experiences, usually lay out, well-labeled, clear and clear, and people are easy to read. When reading a circuit diagram, it is not necessarily your fault.
The printed circuit board is a change in the principle of circuit diagram to the real thing. It is the way to go to the market from the design phase to the market.
Seeing the printing board is simpler than the schematic, as long as you know the conductors, insulator and common electronic components, you can draw a circuit schematic according to the printed board.
In the case of more components, it is a very fortunate thing to have a circuit schematic to detect and repair the printed circuit board.
Since the hands-on electronic small production is also good, help others repair, this is the best time for you have intensive experience, learning technology. Experience is accumulated.
A very complex line or a very precise product, it is often necessary to use double-sided circuit boards and multi-layer circuit boards.
The intermediate layer of the plate can also have a wiring in the middle of the board in the inner and outer layers of the wire plate. In addition to high-density mounting elements, multilayer plates can also be shielded and increased.
When you find a small resistance or small capacitance on the board, don't look directly, please find the triode or integrated circuit connected to them, find them, so fast.
Observe the connection of the circuit board and the copper foil line connection, observe the copper foil line to go, can be placed with the light, put the lamp in one side with copper foil lines.
Electronic engineer must have basic knowledge (16)
The capacitor is a container that can be charged, as is like a cup of water. Therefore, the capacitor can perform charging and discharge, and the magnitude of the charge and discharge is determined by the capacity of the capacitor. There are many types of capacitors, the most common electrolytic capacitance (large capacity, positive and negative poles), ceramic capacitance (small capacity, no positive negative electrode, temperature characteristics), polyester capacitance (polyester film capacitance, small capacity, temperature Good characteristics), etc.
The main parameters of ceramic capacitors are capacity and withstand voltage, and the high-pressure ceramic capacitance of high-pressure resistance of special purposes will indicate a pressure resistance. The use of ceramic capacitors does not require a positive negative electrode, and both ends can be arbitrarily exchanged. Porcelain capacitors are usually operating in high frequency.
Inductance is an electromagnetic conversion element, and electrically can generate magnetic and magnetic can generate electricity. The change in the magnetic field in the inductor will result in a change in current; the change in current can also generate a change in magnetic field.
The interaction of current and magnetic field in inductors always hinders each other. The power transformer is the use of electromagnetic conversion mutual computing to complete the transformer effect.
The main role of inductance in the circuit is resistant to alternating current, direct flow, resistant to high frequency alternating current, and low frequency alternating current. Inductance is often used in transformers, resonant circuits, etc.
Electronic engineer must have basic knowledge (sevente)
The transverse voltage is too high and the forward current may make the diode permanent damage, the damage of the diode and other transistors is mainly because the power consumption is too large (reverse high pressure breakdown instantaneous power consumption) causes PN junction physical damage.
We can regard the triode as the resistance that the resistance value can be mastered, and the range of resistance can be changed to zero to infinity. Therefore, the triode can be used to design amplifying circuits and switching circuits.
Three tubes, collectors, emitters and bases in the triode. The base is used to control the amplification of the two poles to the current. Analysis of current and voltage changes is to analyze the working state of the triode.
The role of the field effect and the effect of the triode are basically exactly the same. Field effect tubes are usually three pins, named source, drain and gate. The gate is used to control the amplification of the different poles to the current.
The triode is a change in the magnification of the base current to control the additional two poles, and the field effect tube is a high and low variation of the gate voltage to control the additional two poles, and the field effect tube gate is substantially no need to consume the current.
Field effect tubes are also divided into two types, N-channels and P-channels. However, the field effect tube is a voltage controlled device, and the lower power supply voltage is difficult to play its excellent performance.
Three pins, anodes, cathodes, and controlles (also known gate). The control is extremely used to control the disconnection of the other two poles to the current. Controllable silicon controls current control can only be turned on or disconnected.
The main role of thyristosil is used to switch, which is an electronic switch without a mechanical contact, a spark, and high speed. Some books are also known as thyristors for thyristors.
Electronic engineer must have basic knowledge (18)
There is an integrated circuit called a membrane circuit (a thick film integrated circuit and film integrated circuit), and its integrated process is made of resistance and wiring on a surface of insulating silicon; and the diode, the diode is not on the silicon wafer. Directly diffused, just mounted them on this surface, then encapsulate the entire circuit with plastic.
The same is equivalent to a multiplication circuit. There are usually two or more inputs. There are four basic rules: 1 × 1 = 1, 1 × 0 = 0, 0 × 1 = 0, 0 × 0 = 0.
It can be obtained to obtain 1 × 1 × 1 = 1, 1 × 0 × 0 = 0, 1 × 0 × 0 = 0, 0 × 0 × 0 = 0, etc.
Or the door circuit is equivalent to a plus circuit. There are usually two or more inputs. There are four basic rules: 1 + 1 = 1, 1 + 0 = 1, 0 + 1 = 1, 0 + 0 = 0.
Can be obtained from 1 + 1 + 1 = 1, 1 + 1 + 0 = 1, 1 + 0 + 0 = 1, 0 + 0 + 0 = 0, etc.
The non-gate circuit is equivalent to a reverse circuit, there is only one input. There are only two cases: 1 = 0, 0 = 1.
The logical relationship between the isoform circuit is relatively special, and there are only two inputs. There are only four cases: 0 + 1 = 1, 1 + 0 = 1, 0 + 0 = 0, 1 + 1 = 0.
With the non-gate circuit, it will be reversed with the results of the door, or the non-door circuit is the result of the gates, and the different or non-door circuit is to reverse the results of the same or the door. "
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