- #1
Mohamed Abdul
Homework Statement
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1. Using the Schematic of a 555 in astable mode from the Wikipedia entry on '555 Timer IC," resistor R1 = 8 kOhms and capacitor C = 3 micro-Farads. Determine the value of R2 so that the output duty cycle is D = 0.7. Note that D is not expressed as a percentage here for simplicity. Express your answer in kOhms.
2. Determine the average value of a square wave whose minimum value is 0 Volts, whose maximum value is V = 10 Volts and whose duty cycle D = 73 %. Express your answer in Volts.
Homework Equations
DC = high time/low time
high time = ln(2)*C*(R1+R2)
low time = ln(2)*C*R2
average value = D*V1 + (1-d)*V2 <= Not sure if this is the right equation
The Attempt at a Solution
For number 1, I set my high time and divided it by the low time. I managed to cancel out the ln(2)*C and got that duty cycle was (R1+R2)/(R1+2R). After setting that equal to .7, I got that R2 was 6kOhms.
For number 2, I plugged in my values for the last equation, using O volts as V1 and 10 volts as V2. This gave me an answer of 2.7 volts.