audioguru2
- Apr 6, 2004
- 12,026
- Joined
- Apr 6, 2004
- Messages
- 12,026
Hi Guys,
In another post we have discussed that components of a project are not needed but someone disagreed.
This circuit consists of 741 opamps U2 to U4. U3 is "supposed" to buffer the output of U2 from the loading effect of R11 which is 2.5K. R9 is "supposed" to limit the current from the loading effect of the input of U4.
The 741 opamp is rated to drive a minimum load of 2K ohms. The input impedance of U4 is 2M ohms.The 75 ohms open-loop output impedance of U2 is reduced by its feedback to only 0.6 milli-ohms. Therefore the "loading" effect of R11 and the input of U4 on the output of U2 is next to nothing.
U3 and R9 are not needed.
View attachment 35971
In another post we have discussed that components of a project are not needed but someone disagreed.
This circuit consists of 741 opamps U2 to U4. U3 is "supposed" to buffer the output of U2 from the loading effect of R11 which is 2.5K. R9 is "supposed" to limit the current from the loading effect of the input of U4.
The 741 opamp is rated to drive a minimum load of 2K ohms. The input impedance of U4 is 2M ohms.The 75 ohms open-loop output impedance of U2 is reduced by its feedback to only 0.6 milli-ohms. Therefore the "loading" effect of R11 and the input of U4 on the output of U2 is next to nothing.
U3 and R9 are not needed.
View attachment 35971
