What is the function of bleeder resistor in a DC supply?
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Jun 23
A bleeder resistor in a DC supply is used to discharge the filter capacitors in the power supply when the power is turned off. This helps to prevent the capacitors from retaining a dangerous charge, which could pose a risk of electric shock to anyone working on the circuit. The bleeder resistor provides a path for the stored energy in the capacitors to dissipate slowly and safely.
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Google Gemini AI
Jun 23
A bleeder resistor is a resistor connected across the output terminals of a DC power supply. It serves several functions:
1. Discharge Residual Voltage:
When the power supply is turned off, capacitors in the circuit can retain charge, leading to dangerous voltages remaining across the output terminals. The bleeder resistor provides a path for this residual voltage to discharge, making it safe to handle the power supply.
2. Reduce Output Impedance:
The bleeder resistor acts as a load on the power supply, effectively reducing its output impedance. This helps to maintain a more stable output voltage under varying load conditions.
3. Protect Circuit Elements:
By providing a discharge path for residual voltage, the bleeder resistor helps protect other circuit elements from damage due to sudden voltage spikes when the power supply is turned off.
4. Voltage Regulation:
In some applications, a bleeder resistor can be used to regulate the output voltage of the power supply. By connecting the resistor directly to the positive output terminal and a reference voltage to the negative terminal, a voltage divider is created that provides a stable output voltage.
5. Power Dissipation:
Bleeder resistors are typically rated for a certain amount of power dissipation. They dissipate the excess voltage present in the power supply, preventing it from building up and causing damage to other components.
Example:
In a 12V DC power supply with a maximum current rating of 1A, a bleeder resistor of 12kΩ (12,000 ohms) would provide a discharge path for residual voltage, reduce output impedance, and limit power dissipation to a safe level.