Need help AC coupling push pull amplifier with op amp

Thread Starter

brianmullins222

Joined Nov 12, 2020
3
I have an AC input of 0-5V that i need to go from -2.5 to 2.5V. this will then go through an op amp and then trough a push pull amplifier configuration. I just cant seem to find a value for the capacitor that will work, so if someone could explain where im going wrong that would be greatly appreciated. The input frequency is 1Hz.
Capture.PNG
 

Marc Sugrue

Joined Jan 19, 2018
213
I have an AC input of 0-5V that i need to go from -2.5 to 2.5V. this will then go through an op amp and then trough a push pull amplifier configuration. I just cant seem to find a value for the capacitor that will work, so if someone could explain where im going wrong that would be greatly appreciated. The input frequency is 1Hz.
View attachment 224842
C1 Needs to be a Lot Bigger, at 1Hz
yes i just couldnt find any formulas for the problem. i think i got it working fairly well at 10u and 100k
The capacitive reactance of the capactor in Ohms (Xc) is 1/(2*pi*F*C). Any capacitor will do DC blocking but to allow 1Hz to pass a 10uF would approximate a 16k Ohms impedance.
 

Audioguru again

Joined Oct 21, 2019
3,193
1Hz is almost DC. The signal generator is grounded so if it has no output coupling capacitor then its DC output is 0V and the input capacitor feeding the opamp is not needed.
 
Top