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The Epson F173090 is a remarkable printhead designed and manufactured by Epson, a renowned leader in printing technology. Known for its precision and reliability, the Epson F173090 is part of Epson’s advanced line of piezoelectric printheads, which utilize innovative technology for on-demand inkjet printing. With a configuration of 90 nozzles for each color, including black, this printhead ensures exceptional printing quality, delivering clear and vibrant images.

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Highlights from Shanghai APPP Expo Exhibition

Johope showcased its latest line of printer parts from February 28 to March 2 at the Shanghai APPP Expo, injecting new vitality into the printing industry.

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The differences between power frequency transformer and high frequency transformer

The principle of power frequency transformer

Power frequency transformers are also called low frequency transformers to show that they are different from high frequency transformers used in switching power supplies. Power frequency transformers have been used in large quantities in traditional power supplies in the past, and the stability of these power supplies uses linear adjustment, so those traditional The power supply is also called a linear power supply. The power frequency generally refers to the frequency of the mains electricity, which is 50Hz in our country and 60Hz in other countries. The transformer that can change the voltage of alternating current at this frequency is called a power frequency transformer.

Design principle of power frequency transformer

1. There are two ways to reduce the amount of copper. One is to reduce the wire diameter, which means that the copper resistance increases, and the copper loss will increase. The second is that reducing the number of turns will increase the no-load current, and the same no-load loss will increase. If the transformer is in the standby state for a long time, the waste of power resources is very large. Every year, the waste of electricity in our country due to the long-term standby and energization of household appliances is in the billions of dollars.

2. When the transformer is designed, the copper loss and the iron loss should be equal, so that the transformer has the lowest loss and the most stable operation. If a transformer is designed, in order to save copper wires, a smaller wire diameter and a method of reducing the number of turns should be adopted. , So that there is a lot of space for the core window, which means that the size of the core is selected too large, resulting in a waste of the core. Due to the large size of the core, the average circumference of the winding is also large, which will also cause the copper wire Increase in dosage. According to the price, the cost of the core is higher than the cost of the copper wire.

Therefore, in the design, under the condition of ensuring that the performance meets the customer's requirements, small iron cores should be selected as far as possible. 41 can be used, but 48 can never be used. Regarding the no-load current, it is better to keep it as low as possible from the perspective of saving standby losses.

The difference between power frequency transformer and high frequency transformer 1. Magnetic materials The power frequency transformer uses silicon steel sheet as the core material; the high frequency transformer uses the ferrite core material.

2. Working frequency The working frequency of the power frequency transformer generally refers to the power frequency of 50HZ or 60HZ; the working frequency of the high frequency transformer is generally above 1KHZ, even tens of KHZ or hundreds of KHZ, and the application range is different with different frequencies.

3. Application Power frequency transformers are generally used to convert 220V or 110V power frequency high voltage into power frequency low voltage for power supply for the circuit boards of small household appliances (such as soymilk, range hood, audio, etc.). The application range is relatively wide; Widely used (such as mobile phone chargers, electronic ballasts, switching power supplies, color TV power supplies, computer power supplies, LCD drivers and power supplies, etc.).

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What is sensitive resistor?

An overview of sensitive resistor

Sensitive resistor is a special resistor that is sensitive to analog quantities such as light intensity, pressure, humidity, etc. When selecting, not only should pay attention to its rated power, maximum working voltage, nominal resistance value, but also parameters such as the maximum working temperature and resistance temperature coefficient, and pay attention to the direction of resistance change.

Types and characteristics of sensitive resistors

At present, there are many types of sensitive resistors. The more common ones are thermistors, photoresistors, varistors, force-sensitive resistors, magnetoresistors, humidity-sensitive resistors and gas-sensitive resistors, which are briefly introduced below.

1. Thermistor

Thermistor is a kind of resistor whose resistance value is very sensitive to temperature. This kind of resistance is generally made of single crystal, polycrystalline and other semiconductor materials. There are many kinds of them. For example, according to the temperature of the resistance, the resistance can be divided into The negative temperature coefficient thermistor whose resistance decreases with the increase of temperature and the positive temperature coefficient thermistor whose resistance increases with the increase of temperature; for example, according to the magnitude and speed of change of resistance with temperature; it can be divided into slow-change type and sudden change type There are two types; if divided by the way the resistor is heated, it can be divided into two types: direct heating and indirect heating; according to its shape and structure, it can also be divided into rod, round, square, bead, and wire Tubular, thin-film and thick-film thermistors, the main features of thermistors are high sensitivity to temperature, low thermal inertia, long life, small size and simple structure. It is widely used in the fields of temperature measurement, control, fire alarm, meteorological sounding, microwave and laser power measurement.

2. Photoresistor

Photoresistor is a kind of resistance element made according to the principle of semiconductor light effect. Its resistance can change with the intensity of incident light. Photoresistors are generally composed of glass substrate, photosensitive layer, electrode and other parts. The materials used in the layer can be divided into polycrystalline photoresistors and single crystal photoresistors. According to the spectral persistence of photoresistors, they can be further divided into ultraviolet photoresistors, visible light photoresistors and infrared photoresistors. UV photoresistors are very sensitive to ultraviolet light and can be used to detect ultraviolet rays; visible photoresistors are mainly used in various photoelectric automatic control systems, mainly photoresistors such as selenium, cadmium sulfide, cadmium selenide, zinc sulfide, etc., generally used in various Photoelectric automatic control system.

3. Varistor

Varistor is a kind of sensitive resistor whose resistance value decreases sharply when voltage is applied at both ends to a certain value. According to different materials, it can be divided into silicon carbide varistor, silicon varistor, and metal oxide. Material varistor and barium titanate varistor, etc. According to its structure, it can be divided into body varistor, junction varistor, single particle laminated varistor and thin film varistor, etc. According to its volt-ampere characteristics, it can be divided into symmetric varistor and asymmetric varistor. Its performance parameters are nominal voltage, nominal current, non-linear coefficient, current capacity and voltage temperature coefficient, etc. Varistors are mainly used in overvoltage protection and voltage stabilization circuits.

4. Magneto-sensitive resistor

Magnetoresistor is also called magnetron resistor. It is made by using the magnetoresistance effect. Its salient feature is that the relationship between the resistance value and the magnetic field increases according to the square law in a weak magnetic field, and increases linearly in a strong magnetic field. The magnetoresistance has high sensitivity, but The direction of the magnetic field cannot be judged, and it is greatly affected by temperature, and the resistance of the magnetoresistor changes with the change of the magnetic field. Using the change of the magnetoresistor, the displacement of the magnetic field relative to the magnetoresistor can be accurately measured. The magnetoresistor can also be used to make contactless switches, which has great achievements in measurement technology, automatic control and signal processing.

5. Force sensitive resistor

If pressure is applied to the semiconductor crystal, in addition to the deformation, the symmetry inside the crystal will change, that is, the conduction mechanism will change, so that the conductivity of the crystal will also change. This kind of external force causes the resistivity of the semiconductor material to change. The phenomenon is called the piezoresistive effect of semiconductors. This principle is also the manufacturing principle of force-sensitive resistors. Force-sensitive resistors can realize electrical conversion of physical quantities such as force, displacement, and torque. Therefore, it can be used to make torque meters, ductility meters, tensiometers, accelerometers, semiconductor microphones and various pressure sensors.

6. Gas sensitive resistor

This is a kind of sensitive resistor made by using the characteristics of the semiconductor surface to absorb a certain gas molecule and then undergo oxidation or reduction reaction to change the resistivity. Generally, it is divided into N-type and P-type according to the ratio and structure of the materials. When N-type gas-sensitive semiconductor encounters reducing gas, it is adsorbed on its surface in a positive ion state, which increases the electron density of the conduction band, thereby reducing the resistance. The resistance of P-type metal oxide special semiconductor increases when it encounters a gas that can provide electrons, and when it encounters an oxidizing gas that attracts electrons, the resistance decreases. Gas sensitive resistors are also a new type of semiconductor components, which can be made into various gas sensitive detectors, which have a unique role in leak detection, environmental monitoring, fire prevention and automatic control of various pipelines and sealing systems.

7. Humidity resistor 

Humidity-sensitive resistor is a sensitive element whose resistance changes with the relative humidity of the environment. It is composed of a moisture-sensitive layer, an electrode and an insulating substrate with a certain mechanical strength. When the moisture-sensitive layer absorbs the moisture in the environment, it causes a change in the resistance between the two electrodes. This kind of sensitive resistor is used to make hair hygrometer and wet and dry spherometer with very high accuracy, so it is often used in the field of humidity measurement and control.

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Functions and working principle of the operational amplifier

Functions

The role of the operational amplifier is to amplify the signal. Sensor + operational amplifier + ADC + processor is a typical application circuit of operational amplifier, this circuit for the amplification of weak signals, only a single amplifier is difficult to achieve good results, we must use some more special methods and sensor excitation means, and use synchronous detection The circuit structure can get very good measurement results. This kind of synchronous detection circuit is similar to the lock-in amplifier structure, including the square wave excitation of the sensor, the current-to-voltage amplifier, and the synchronous demodulation. It should be noted that the current-to-voltage amplifier needs to use an op amp with a very low input bias current.

Working principle

The working principle of the operational amplifier is that for a dual power supply operational amplifier, its output can be changed on both sides of zero voltage, and the output can also be set to zero when the differential input voltage is zero. The operational amplifier adopts a single power supply, and the output changes in a certain range between the power supply and the ground. The input potential of the op amp is usually required to be higher than a certain value of the negative power supply and lower than a certain value of the positive power supply. The specially designed operational amplifier can allow the input potential to vary from the negative power supply to the positive power supply, even slightly higher than the positive power supply or slightly lower than the negative power supply. This kind of op amp is called a rail-to-rail input op amp. The output signal of the operational amplifier is proportional to the signal voltage difference between the two input terminals. In the audio segment: output voltage = A0 (E1-E2), where A0 is the low-frequency open-loop gain of the operational amplifier (such as 100dB, which is 100000 times) , E1 is the input signal voltage at the non-inverting terminal, and E2 is the input signal voltage at the inverting terminal.

Learn more detailed information about the operational amplifier on Easybom.

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What is an SMD Electrolytic Capacitors?

SMD electrolytic capacitors In terms of current output, aluminum electrolytic capacitors occupy the second place among capacitors. This type of capacitor was originally a general DC capacitor, but now it has developed from DC to AC, from low temperature to high temperature, from low voltage to high voltage, from general to special, from general structure to chip, flat, book式等结构。 Equations and other structures. The upper limit capacity has been extended to about 4F, the operating frequency has reached 30kHz, the operating temperature range has reached -55℃-125℃, and some even reached 150℃, and the rated voltage has reached 700V. In short, the development of aluminum electrolytic capacitors is becoming wider and wider.

Principle of SMD Electrolytic Capacitor

SMD electrolytic capacitors are usually made of metal foil (aluminum/tantalum) as the positive electrode, and the insulating oxide layer of the metal foil (aluminum oxide/tantalum pentoxide) as the dielectric. Electrolytic capacitors are divided into aluminum electrolytic capacitors and aluminum electrolytic capacitors based on their positive electrodes. Tantalum electrolytic capacitors. The negative electrode of aluminum electrolytic capacitors is made of thin paper/film or electrolytic polymer impregnated with electrolyte (liquid electrolyte); the negative electrode of tantalum electrolytic capacitors usually uses manganese dioxide. Since the electrolyte is used as the negative electrode (note that it is distinguished from the dielectric), the electrolytic capacitor gets its name.

SMD electrolytic capacitor function

SMD electrolytic capacitors usually play the role of power supply filtering, decoupling, signal coupling, time constant setting, and DC blocking in power circuits or intermediate frequency and low frequency circuits. Generally, it cannot be used in AC power circuits. When used as filter capacitors in DC power circuits, its anode (positive) should be connected to the positive terminal of the power supply voltage, and the cathode (negative) should be connected to the negative terminal of the power supply voltage. , Otherwise it will damage the capacitor. Non-polar electrolytic capacitors are usually used in speaker frequency divider circuits, TV S correction circuits and single-phase motor starting circuits. Electrolytic capacitors are widely used in household appliances and various electronic products, with a large capacity range, generally 1~1000μF, and a rated working voltage range of 6.3~450V. Its disadvantages are medium loss, large capacity error (the maximum allowable deviation is +100%, -20%), poor high temperature resistance, and prone to failure due to long storage time.

Look through Easybom to learn more detailed information about the capacitors.

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How does Capacitors Work?

When the capacitor is not charged, the positive and negative charges inside the capacitor will be combined due to the action of the opposite sex. Because of the mutual cancellation, there will be no potential difference and no voltage. But the charge will move under the action of the electric field force: under the action of the external electric field, the negative charge of the capacitor will run to the negative electrode of the capacitor through the external power supply. The negative electrode of the capacitor is negatively charged due to the negative charge, and the positive electrode of the capacitor is lost. It is negatively charged so it is positively charged. Because the two electrodes of the capacitor are insulated from each other, the separated charge cannot automatically return to its original position. If we discharge the capacitor, the positive and negative charges are recombined. This is how the capacitor works.

Learn more detailed information about the capacitor on Easybom.

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What should I do if the power capacitor has discharge noise?

When the capacitor is in operation, there is generally no sound, but sometimes there are exceptions. The reasons for the sound are roughly as follows: 

(1) Casing discharge. The bushing of the capacitor is assembled. If it is left in the open for too long, rainwater will enter between the two bushings. After the voltage is applied, crackling discharge sound may be produced. In this case, loosen the outer sleeve, wipe it dry and reinstall it. 

(2) Lack of oil discharge. If there is a serious shortage of oil in the capacitor, so that the lower end of the bushing is exposed to the oil surface, there may be a discharge sound. For this reason, capacitor oil of the same specification should be added. 

(3) Desoldering discharge. If there is false welding or desoldering inside the capacitor, it will flash over and discharge in the oil. If the discharge does not stop, it should be disassembled and repaired. 

(4) Poor grounding discharge. When the core of the capacitor is in poor contact with the case, a floating voltage will appear, causing discharge noise. At this time, as long as the capacitor is shaken to make the core contact with the shell, the discharge sound can disappear.

It will help you solve some related problems about the capacitor.