Refer to the Schmitt trigger circuit and the following specifications. Given R2 = 80 kΩ, ±Vs = ±11V. Determine the value for R1.
High output voltage level, VoutH = +4.5 V
Low output voltage level, VoutL = -5.0 V
Upper threshold voltage, VUTP = +2.0 V
Lower threshold voltage, VLTP = -2.5 V
Express your answer with two decimal places.
To determine the value for R1, we can use the formula for the upper threshold voltage of a Schmitt trigger circuit:
VUTP = VoutL * (R1 / (R1 + R2))
Plugging in the given values:
2.0 V = -5.0 V * (R1 / (R1 + 80 kΩ))
Rearranging the equation to solve for R1:
2.0 V * (R1 + 80 kΩ) = -5.0 V * R1
2.0 V * R1 + 160 kΩ = -5.0 V * R1
7.0 V * R1 = -160 kΩ
R1 = (-160 kΩ) / (7.0 V)
R1 = -22.857 kΩ
Since resistance cannot be negative, we can take the absolute value:
R1 = 22.86 kΩ
Therefore, the value for R1 is 22.86 kΩ.
To determine the value for R1, we can use the formula for the threshold voltages of a Schmitt trigger circuit:
VUTP = ± Vs * R2 / (R1 + R2)
VLTP = ± Vs * R2 / R2
From the given specifications, we can substitute the values:
VUTP = +2.0 V
Vs = ±11V
R2 = 80 kΩ
Let's calculate the value for R1 using the upper threshold voltage:
2.0 = 11 * 80000 / (R1 + 80000)
Now, we can solve this equation for R1:
2.0(R1 + 80000) = 11 * 80000
2.0R1 + 160000 = 880000
2.0R1 = 720000
R1 = 720000 / 2
R1 = 360000
Therefore, the value for R1 is 360000 Ω (or 360 kΩ)