In a zero crossing detector, Calculate the rise time of the output voltage if the slew rate of op-amp is 70 V/us. Assume Vs = 10 V.
To calculate the rise time of the output voltage in a zero crossing detector, we need to consider the characteristics of the op-amp and the input signal.
The rise time (tr) is the time it takes for the output voltage to rise from 10% to 90% of its final value. However, in a zero crossing detector, the output voltage switches between the positive and negative supply voltages. Therefore, we need to consider both the rising and falling edges of the output voltage.
Since the voltage swing of the output voltage is from the negative supply voltage (-Vs) to the positive supply voltage (+Vs), the total voltage change is 2Vs.
We can use the formula for rise time:
tr = Voltage Change / Slew Rate
Voltage Change = 2Vs = 2 * 10 V = 20 V
Slew Rate = 70 V/μs
tr = 20 V / 70 V/μs
= 0.286 μs
To calculate the rise time of the output voltage in a zero crossing detector, we need to consider the relationship between the slew rate of the op-amp and the input signal. The rise time can be estimated using the formula:
Rise Time (tr) = (0.35 / Slew Rate) * (Vin_max - Vin_min)
Where:
- tr is the rise time,
- Slew Rate is the slope of the voltage transition,
- Vin_max is the maximum input voltage, and
- Vin_min is the minimum input voltage.
In this case, the input voltage (Vin) is not specified, so we will assume that the maximum input voltage is Vs (10 V) and the minimum input voltage is 0 V.
Given:
- Slew Rate (SR) = 70 V/µs
- Vin_max = 10 V
- Vin_min = 0 V
Now, we can substitute the values into the formula and calculate the rise time:
Rise Time (tr) = (0.35 / 70) * (10 - 0)
Rise Time (tr) = 0.005 s or 5 ms
Therefore, the rise time of the output voltage in the zero crossing detector is 5 ms.