Precautions for the use of linear DC power supplies commonly used in daily life

“With the diversified development of the world, our lives are constantly changing, including the various Electronic products we come into contact with. Then you must not know some of the components of these products, such as linear DC power supplies.

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With the diversified development of the world, our lives are constantly changing, including the various electronic products we come into contact with. Then you must not know some of the components of these products, such as linear DC power supplies.

During the operation of the linear DC power supply, pay attention to the following items, which can effectively avoid unnecessary troubles.

1) Voltage setting: Turn on the DC power switch and adjust the voltage knob to adjust the voltage reading to the required working electrical connection. When you need to lower the voltage, turn the potentiometer slowly to make the speed of the voltmeter drop compatible with the speed of the manual adjustment knob.

The power transformer converts the AC input voltage (for example, 220V, 50Hz) from the power grid into a lower AC voltage (for example, 9V, 12V, 15V, etc.).

2) Constant current setting: Connect the load, first set the current adjustment potentiometer to the minimum. Turn on the DC power supply and adjust the current to the desired current value.

The power transformer usually has two or more windings. Among them, the winding connected to the AC power supply is called the primary winding, and the remaining windings are called the secondary winding. The primary winding and the secondary winding are electrically insulated. Therefore, the power transformer achieves electrical isolation from the power grid while changing the voltage amplitude.

3) Voltage protection value setting: First turn the voltage protection knob to the maximum, adjust the output voltage to the required protection value, and then slowly adjust the DC power supply voltage protection potentiometer counterclockwise until the DC power supply has overvoltage protection. The voltage protection value should generally be about 10% higher than the working voltage, so adjust the output voltage to about 10% higher than the required voltage, and then slowly adjust the voltage protection potentiometer counterclockwise until the DC power supply has overvoltage protection.

The rectifier circuit transforms the alternating positive and negative sinusoidal AC voltage into a unidirectional pulsating DC voltage through a semiconductor diode with unidirectional conductivity.

4) Current alarm value setting: First turn the current alarm knob to the maximum, adjust the output current to the required alarm value, and then slowly adjust the current alarm potentiometer counterclockwise until the power supply emits an audible and visual alarm.

The rectifier circuit usually selects a bridge rectifier composed of 4 diodes, referred to as a rectifier bridge. The pulsating DC voltage output by the rectifier circuit contains a large AC component and cannot be used directly by the electronic circuit. The filter circuit needs to be connected after the rectifier circuit.

5) When the DC power supply is switched on or released from the load, the reading of the voltmeter will jump instantaneously, which is a normal phenomenon.

In small and medium power linear power supplies, capacitor filter circuits are usually used, and the filter capacitor is directly connected in parallel with the output end of the rectifier circuit to form a capacitor filter circuit. The filter circuit can filter out most of the AC components in the pulsating DC voltage, making it a relatively smooth DC voltage.

6) After shutting down, if you need to turn on the DC power supply again, please wait a while and do not switch the machine frequently, otherwise the power supply may be damaged.

In the process of research and design, there must be problems of this kind or that kind, which requires our scientific research workers to constantly sum up experience in the design process, so as to promote the continuous innovation of products.