Ham Amateur Radio Technician Practice Exam

What is the function of a power supply bleeder resistor?

1. It amplifies the voltage

2. It discharges the filter capacitors when power is removed

3. It regulates the voltage output

4. It protects against overload

The correct answer is: It discharges the filter capacitors when power is removed

The function of a power supply bleeder resistor is to discharge the filter capacitors when power is removed. When power supplies operate with filter capacitors, these capacitors can retain a significant charge even after the power has been turned off, which can pose a safety hazard if someone were to come into contact with the system or try to service it. The bleeder resistor is connected in parallel with the capacitors and provides a path for the stored charge to dissipate gradually after the power is removed. This ensures that the voltage across the capacitors decreases to a safe level and helps prevent potential electrical shocks or damage to components when the power is turned off. The other functions mentioned, such as amplifying the voltage or regulating the voltage output, are not associated with a bleeder resistor. It does not provide overload protection either, as that function would typically be handled by other components specific to overload protection designs. Thus, the correct answer highlights the essential safety function of the bleeder resistor in power supply circuits.