To find the average value of the output voltage, we first need to analyze the circuit.
Step 1: Identify the circuit type and output waveform.
The circuit shown is a half-wave rectifier. The input voltage is vi=Vmsin(ωt).
- During the positive half-cycle of the input voltage (0≤t≤T/2), the diode is forward-biased (assuming an ideal diode with 0V drop). Thus, the output voltage vo is equal to the input voltage vi.
vo(t)=Vmsin(ωt)for0≤t≤T/2
- During the negative half-cycle of the input voltage (T/2<t≤T), the diode is reverse-biased. It acts as an open circuit, so no current flows through the resistor R. Therefore, the output voltage vo is 0.
vo(t)=0forT/2<t≤T
Step 2: Calculate the average value of the output voltage.
The average value of a periodic waveform vo(t) over one period T is given by the formula:
Vavg=T1∫0Tvo(t)dt
Substitute the output voltage waveform into the integral:
Vavg=T1[∫0T/2Vmsin(ωt)dt+∫T/2T0dt]
Vavg=T1∫0T/2Vmsin(ωt)dt
Step 3: Perform the integration.
We know that ω=T2π.
Vavg=TVm[−ωcos(ωt)]0T/2
Vavg=−ωTVm[cos(ω2T)−cos(0)]
Substitute ωT=2π:
Vavg=−2πVm[cos(T2π2T)−cos(0)]
Vavg=−2πVm[cos(π)−cos(0)]
Vavg=−2πVm[−1−1]
Vavg=−2πVm(−2)
Vavg=2π2Vm
Vavg=πVm
Step 4: Convert to decimal value.
Using the approximation π≈3.14159:
Vavg≈3.141591Vm≈0.3183Vm
Comparing this result with the given options:
A) Vm
B) 0.5Vm
C) 0.318Vm
D) 0.636Vm
The calculated average value matches option C.
The final answer is C.