Factors causing voltage instability in circuit boards
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Factors causing voltage instability in circuit boards

Posted Date: 2024-02-07

One of the important causes of circuit board failure is the instability of the operating voltage supplied to the circuit board. So under what circumstances will voltage instability occur?

Generally speaking, the factors causing voltage instability include the following situations.

Unstable factors of power grid supply voltage. In this case, the transmission line of the transmission network is too long, resulting in large losses during the transmission process, and the capacity of the compensation capacitor in the power grid is reduced. If it is not replaced in time, the voltage will be high and low, and the voltage will fluctuate. Appear. For this situation, you only need to replace the compensation capacitor with a good one, and it will be solved.

Large electrical appliances do not use dedicated transformers and have corresponding measures taken to cause voltage instability. If there are too many large and heavy-load electrical appliances (such as large motors, lifting equipment, etc.) on the transmission line, and they are started frequently without the installation of step-down starting protection, the large starting current will cause the The voltage of the power grid is instantly pulled down. After normal startup, the voltage will rise back to the original voltage value, causing the voltage to be high and low. In this case, it is necessary to add a voltage-reducing starting device (usually a soft starter or frequency converter) to large electrical appliances so that the grid voltage will not be lowered when starting to solve the problem.

The anti-interference protection circuit in the input power circuit is imperfect, and interference pulses are mixed into the input power circuit, causing voltage instability. This situation is generally caused by the designer not doing a good job in preventing interference circuits in order to reduce costs or not thinking carefully during the design, causing some interference sources to enter the circuit board along with the input power supply, causing the voltage supplied to the circuit board to be high and low, resulting in Circuit board failure. In this case, as long as anti-interference circuit components are added to the input circuit, the voltage may be high and low due to interference.

What is the reason why the circuit board voltage is not enough?

Insufficient circuit board voltage can be caused by a number of reasons. Here are some possible reasons:

1. Power supply problem: One of the most common reasons is that the voltage output by the power supply itself is unstable or the power supply voltage is too low. The power supply may be faulty, and the supply voltage is either lower than the set value, or the output cannot be stable when the load changes. Check whether the power supply is working properly and make sure its output voltage meets the requirements.

2. Power cable issues: A poor connection or damage to the power cable can cause voltage drop. Check the power line to make sure the power cable is connected correctly and securely and is not broken or damaged.

3. High current load: If the load on the circuit board is too large, it will cause the current to increase, thus reducing the voltage. This can be caused by issues such as overloading or short circuiting. Check the load on the circuit board to make sure it is within the range that the power supply can support.

4. Circuit board design issues: Unreasonable circuit board design or failure to properly adjust circuit parameters after replacing components may cause voltage drops. Review the board design to ensure that the board layout and component selection meet requirements. If the circuit board design is modified or components are replaced, the circuit parameters need to be re-evaluated and adjusted.

5. Component problems: Faulty or inappropriate selection of components on the circuit board (such as resistors, capacitors, diodes, etc.) may cause insufficient voltage. Check whether components are damaged or need to be replaced, and make sure the components you choose meet the circuit requirements.

Why is there voltage but no current on the circuit board?

There are several reasons why the circuit board has voltage but no current:

1. Open or broken circuit: There may be an open or broken circuit in the circuit, preventing the current from flowing. Check the connections, wires, and components on the circuit board to make sure there are no open or broken circuits.

2. Component failure: Some components may be damaged or failed, such as switches, relays, resistors, capacitors, etc. A faulty component may block the flow of electrical current. Check these components and troubleshoot one by one.

3. Wrong component selection or value: If the components on the circuit board are incorrectly selected or the selected component parameters are inappropriate, the current may not flow normally. Check component specifications and values ​​to ensure they meet design requirements.

4. Power supply problems: The output current limit of the power supply or the failure of the power supply itself may prevent current from flowing. Check whether the current output by the power supply can meet the current consumption required by the circuit board, and ensure that the power supply is working properly.

5. Short-circuit protection function: Some power supplies or circuit boards may have short-circuit protection function, which will actively cut off the current to protect the circuit when the circuit is short-circuited. Check whether the short circuit protection function of the circuit board or power supply is triggered. The current needs to be confirmed and removed before the short circuit can be restored.

6. Bias current or calibration issues: In some circuits, the settings of the bias current or calibration current may affect the flow of current. Check that these current sources are set up correctly and make calibration adjustments if necessary.

These are just some common reasons that may cause voltage and no current on the circuit board. Specific problems may require more detailed analysis and troubleshooting based on the actual situation, such as the specific design of the circuit board, connection method, etc.

Review Editor: Huang Fei


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