- #1
mmmboh
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With regards to this http://www.electronics-tutorials.ws/waveforms/555_oscillator.html, I figured out how to get t2 fine, but I have a problem figuring out how to get t1...I know when the negative-going waveform at pin 2 crosses Vcc/3, pin 3 goes to Vcc, and pin 7 gets internally disconnected, and the capacitor charges to 2Vcc/3.
Now using the formula Vcapacitor=V0(1-e-t/RC), what I think "should" be right is to set it up like this: 2Vcc/3=(Vcc/3)*((1-e-t/(RA+RB)C)...but of course this doesn't make sense, the voltage across the capacitor can't go above the voltage that's charging it. The final capacitor voltage should be half the initial for the equation to work I believe. Can anyone clarify how I am suppose to set this equation up please?
Thanks!
Now using the formula Vcapacitor=V0(1-e-t/RC), what I think "should" be right is to set it up like this: 2Vcc/3=(Vcc/3)*((1-e-t/(RA+RB)C)...but of course this doesn't make sense, the voltage across the capacitor can't go above the voltage that's charging it. The final capacitor voltage should be half the initial for the equation to work I believe. Can anyone clarify how I am suppose to set this equation up please?
Thanks!