Figure 21.53 shows how a bleeder resistor is used to discharge a capacitor after an electronic device is shut off, allowing a person to work on the electronics with less risk of shock.

(a) What is the time constant?

(b) How long will it take to reduce the voltage on the capacitor to 0.250% (5% of 5%) of its full value once discharge begins?

(c) If the capacitor is charged to a voltage V₀ through a 100-Ω resistance, calculate the time it takes to rise to 0.865V₀ (This is about two time constants.)

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Electronic circuit C 80 μF R - 250 ΚΩ