Interview questions of electrical automation

Interview questions of electrical automation

The interview topic of electrical automation is the basic knowledge of this major. Sometimes, according to the specific recruitment position of the unit, there will be questions about a certain aspect. For example, when power plants, power supply stations and other units recruit employees, they will ask about the power supply and distribution knowledge in the factory; For example, cement or chemical plants recruit electricians, so the above questions about circuit and simulation will be asked less, and generally they will ask PLC and related equipment debugging, as well as the basic knowledge about automatic control.

Classical questions in electrical automation interview

1. What is the voltage drop after the diode of silicon material and germanium material is turned on? What will happen to the forward voltage drop and reverse current of the diode after the temperature rises? Try to tell the purpose of diodes (just give three examples)

2. How to test the diode with a multimeter? What main parameters should be satisfied when choosing rectifier diode model? How to determine?

3. In the LED circuit, the forward voltage drop UF= 1.4V, the forward current IF= 10mA and the power supply voltage 5V are known. How to determine the current limiting resistance?

4. When the triode is used in the amplification working state, the potential requirements of each pole are: NPN tube type is C, B and E, and PNP tube type is C, B and E..

5. Field effect transistor is a control device, which controls the electrode current through the electrode voltage. What are the polarities of drain voltages of P-channel and N-channel FET?

6. When the integrated operational amplifier is used for linear amplification, the signal is input from the noninverting terminal. Try to draw its circuit diagram and explain how to get the corresponding resistance.

7. List a common operational amplifier model and point out the importance of input offset voltage.

8. Try to draw the circuit diagram of the proportional-integral circuit composed of operational amplifier, and explain the selection of each component parameter.

9. An electronic circuit needs a set of 5V, 1A DC regulated power supply. Please design a power supply circuit and explain the general selection of required components.

10. What is needed in electronic equipment? 15V two groups of power supplies, load current 200mA, main three-terminal integrated voltage regulator, 1. Draw a circuit diagram 2. Try to determine the effective value and capacity of the transformer secondary voltage.

1 1.TTL circuit and CMOS circuit are the most commonly used in digital electronic circuits. Try to describe the main characteristics and common series models of TTL circuits and CMOS circuits.

12. What is the current? What is the current? What is TTL's ability to drive loads? Is it pulling current or pouring current?

What are the functions of PO□, P 1□, P2□ and P3□ in 13.5 1 series single chip microcomputer?

14. What are the interrupt sources of single chip microcomputer? What are the processes of interrupt handling? The entry address of the interrupt service program is determined by the user, right?

15. There are two main methods to exchange information between computers and peripherals: parallel communication and serial communication. Try to tell their main advantages and disadvantages.

16. Why can I regulator and PI regulator achieve no static error?

Etiquette in job interview:

1. In any case, you should pay attention to knocking at the door before entering the room.

2. Be calm and polite to others.

3. Keep your eyes looking straight and smile.

4. Speak clearly and at a moderate volume.

5. Look focused and don't comb your hair when you speak.

6. Gestures should not be too many, and appropriate coordination is needed.

7. Before entering the interview office, you can chew a piece of gum to eliminate your breath and ease your stable and nervous mood.

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