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An electronic apparatus may have large capacitors at high
Chapter 21, Problem 39(choose chapter or problem)
An electronic apparatus may have large capacitors at high voltage in the power supply section, presenting a shock hazard even when the apparatus is switched off. A “bleeder resistor” is therefore placed across such a capacitor, as shown schematically in Figure \(21.50\), to bleed the charge from it after the apparatus is off. Why must the bleeder resistance be much greater than the effective resistance of the rest of the circuit? How does this affect the time constant for discharging the capacitor?
Figure \(21.50\) A bleeder resistor \(R_{b l}\) discharges the capacitor in this electronic device once it is switched off.
Equation Transcription:
Text Transcription:
21.50
R_bl
Questions & Answers
QUESTION:
An electronic apparatus may have large capacitors at high voltage in the power supply section, presenting a shock hazard even when the apparatus is switched off. A “bleeder resistor” is therefore placed across such a capacitor, as shown schematically in Figure \(21.50\), to bleed the charge from it after the apparatus is off. Why must the bleeder resistance be much greater than the effective resistance of the rest of the circuit? How does this affect the time constant for discharging the capacitor?
Figure \(21.50\) A bleeder resistor \(R_{b l}\) discharges the capacitor in this electronic device once it is switched off.
Equation Transcription:
Text Transcription:
21.50
R_bl
ANSWER:
Solution 39CQ
Step 1 of 2
A electronic apparatus having a large capacitor to accommodate large amount of charge depending upon the requirement of the apparatus, even when the apparatus is switched off the capacitor present in the apparatus stores the charge and when touched directly presents a shock hazard. In order to avoid the shock, a bleeder resistor is placed across such a capacitor to take out the charge which is stored in the capacitor when the apparatus is switched off.