Ten Daily Electronic Common Sense-Section 96

What are the main technical characteristics of the T6321A?

1. The constant current output is 350mA;
2. The input DC voltage range is 6.0～18V;
3. The package type is SOT23-3;
4. The working temperature is -40～85℃;
5. The maximum welding temperature is 260℃.

What are the types of sensors for electronically controlled in-line pumps?

• Rack position sensor
• Fuel injection advance angle sensor

What are the main modulation methods used in RFID systems?

There are usually three modulation methods used in RFID systems:
The modulation of the carrier amplitude is called amplitude keying (ASK-Amplitude Shift keying);
The modulation of the carrier frequency is called frequency shift keying (FSK-Frequency Shift keying);
The phase modulation of the carrier is a digital modulation method called phase keying (PSK-Phase Shift keying).

How to calculate the equivalent capacitance of the transmission line?

Two pieces of information can be drawn from the information of the title:
(1) This transmission line is a high-speed line, without special instructions, the default impedance should be 50 ohms;
(2) This transmission line is a stripline structure. According to the common sense of stripline design, the transmission delay at 50 ohms is about 180ps/in. The equivalent capacitance is the ratio of the transmission delay to the impedance (for the derivation of the relevant formula, please refer to the relevant information of the transmission line). Then the equivalent capacitance value per unit length is: 180/50=3.6PF, and the equivalent capacitance per unit length of the transmission line is usually between 3.5-3.8PF. However, in high-speed PCB design, it is often important to remember some commonly used empirical values, which can sometimes save some tedious calculations.

What are the internal photoelectric effects that can be divided into several categories?

• Photoconductive effect: Under the action of light, electrons absorb photon energy and transition from a bonded state to a free state. The change in the resistivity of the material is caused by a phenomenon called the photoconductive effect. Photoelectric devices based on this effect have photoresistors.
• Photovoltaic effect: The phenomenon that an object can generate an electromotive force in a certain direction under the action of light is called the photovoltaic effect.

What are the specific factors that are unique to RFID technology?

• Application system configuration: hardware configuration, software configuration and commercial costs related to software and hardware.
• RFID frequency band selection: According to different system requirements, RFID technology systems with different frequency bands are selected.
• System usage range: Different RFID systems have different energy distribution and communication ranges.
• Conflict avoidance and system reliability: It is necessary to consider how to reduce and avoid RFID system signal conflict, and to increase the system reliability by some means.

What is the structure and principle of the vane air flow sensor?

Vane air flow sensors are also known as vane or valve air flow sensors. It works on the principle of changing the resistance of the potentiometer by using the thrust of the intake air flow.
Vane air flow sensors are widely used in traditional Bosch L-type engines, Toyota Camry, and Crown sedans. It is mainly composed of blade part and potentiometer part.

What are the ways to reduce interrupt latency through software handlers?

There are 2 ways to shorten interrupt latency by software handler, they are interrupt nesting and using high priority.
Interrupt nesting allows a new interrupt to be serviced while an interrupt is being serviced. Instead of waiting for all interrupt handlers to complete before allowing new interrupts. Once the nested interrupt service is completed, it returns to the previous interrupt service routine.
High priority is to use interrupt priority to interrupt the executing low priority interrupt.

What are the performance of WOLED?

1. Color quality: The color quality of WOLED is mainly represented by CIE chromaticity coordinates, color temperature and color rendering index.
2. Luminous efficiency: The luminous efficiency of WOLED includes quantum efficiency, current efficiency and power efficiency.
3. Device life: The life of WOLED mainly refers to the brightness life, and the brightness life refers to the average working time of the device brightness decaying to 50% or 75% of the initial brightness.

What is a piezoelectric crystal?

There is a very interesting class of crystals that, when you squeeze or stretch it, have different charges on the ends. This effect is called the piezoelectric effect.
The crystals that can produce the piezoelectric effect are called piezoelectric crystals. Crystal (alpha-quartz) is a well-known piezoelectric crystal. If pressure is applied to a slice cut from a crystal in a certain direction, an electric charge will develop on the slice. If the sheet is stretched in the opposite direction, a charge will also appear on the sheet, but with the opposite sign. The more force you squeeze or stretch, the more charge will be on the crystal. If electrodes are plated on both ends of the sheet and an alternating current is applied, the sheet will periodically elongate or shorten, that is, start to vibrate.
This inverse piezoelectric effect has been widely used in science and technology. Piezoelectric quartz flakes can be made of crystals, with an area of ​​only a few square millimeters and a thickness of only a few tenths of a millimeter. Don’t underestimate this small chip, it plays a huge role in radio technology.
As mentioned earlier, in the alternating electric field, the vibration frequency of such a sheet does not change at all. This constant vibration is exactly what is necessary to control frequencies in radio technology. Filters made from piezoelectric chips are found in many electrical devices in your home, such as color TVs, to ensure clarity of images and sound. There is a core component in the quartz electronic watch you wear called a quartz oscillator. It is this key component that guarantees the higher travel time accuracy of quartz watches than other mechanical watches.
Instruments equipped with piezoelectric crystal elements enable technicians to study pressure changes in steam engines, internal combustion engines and various chemical equipment. The use of piezoelectric crystals can even measure the pressure of the fluid in the pipeline, the pressure of the cannon barrel when it fires the shell, and the instantaneous pressure when the bomb explodes.
Piezoelectric crystals are also widely used in sound reproduction, recording and transmission. Piezoelectric chips attached to the microphone convert sound vibrations into changes in electrical current. As soon as the sound wave hits the piezoelectric sheet, an electric charge is generated on the electrodes at both ends of the sheet, and its size and sign change with the sound.
The change in the electric charge on the piezoelectric chip, and then through the electronic device, can be turned into radio waves and transmitted to distant places. These radio waves are received by the radio, and through the vibration of piezoelectric crystal sheets placed on the radio speaker, they become sound and reverberate in the air. Could it be said that the piezoelectric chip in the microphone “hears” the sound, while the piezoelectric crystal sheet on the speaker “speaks” or “sings”.