This HPF has cutoff of 26.54 Hz.
Time constant. Multiply the value of C1 and R3, the units of the product are seconds. You want it to be less than the period of the square wave. If you change the frequency, you may need to change the values.This HPF has cutoff of 26.54 Hz.
how did you determine the value of C1 and R3? I guess C1 is a choose, then how to determine R3?
? It's not in Eric's post #6 sim.You want it to be less than the period of the square wave.
From the suggested R3 and C1 value which gave expected level shifting, we have the time constant as C1*R3=6kohm*1uF=6ms and the period as, T=1/f=1/100KHz=0.01ms. That is the period is less than the RC time constant so the RC time constant cannot be less the period!Time constant. Multiply the value of C1 and R3, the units of the product are seconds. You want it to be less than the period of the square wave. If you change the frequency, you may need to change the values.
There is a square wave to see, with a 10uS period.There's nothing to see
You are right and I miscalculated. The combination of C3 and R1 forms a highpass filter with a corner frequency ofFrom the suggested R3 and C1 value which gave expected level shifting, we have the time constant as C1*R3=6kohm*1uF=6ms and the period as, T=1/f=1/100KHz=0.01ms. That is the period is less than the RC time constant so the RC time constant cannot be less the period!
True.That is the period is less than the RC time constant so the RC time constant cannot be less the period!
Your are correct for the original, bipolar 555 astable circuit. That circuit cannot get to exactly 50/50 without additional parts.The duty cycle equation, d=R1+R2/(R1+2*R2) with d=0.5 always gives R1=0! so is there is no or exact 50% duty cycle for astable operation?
by Aaron Carman
by Jake Hertz
by Jake Hertz