Maker Pro
Maker Pro

Sallen Key Low Pass Filter, bandpass filter

bertus

Moderator
Nov 8, 2019
3,321
Joined
Nov 8, 2019
Messages
3,321
hello,

what is the voltage in the middle of the two resistors?

bertus
 

bertus

Moderator
Nov 8, 2019
3,321
Joined
Nov 8, 2019
Messages
3,321
hello,

the voltage should be on the + input of the opamp:
1711108563895.png

bertus
 

danadak

Feb 19, 2021
767
Joined
Feb 19, 2021
Messages
767
I have not read this entire thread but hanging 10 uF and 100 uF on
the output to ground I would think ill advised due to stability issues.....

1711577195583.png

Regards, Dana.
 

Maglatron

Jul 12, 2023
1,454
Joined
Jul 12, 2023
Messages
1,454
got new proto board going to make a start on the circuit from the beggining with colour coded wires and thats the (mic to pre-amp, amp, and REF GND circuit and then the filters and buffer) hopefully get the right results this time
 

Maglatron

Jul 12, 2023
1,454
Joined
Jul 12, 2023
Messages
1,454
is this be right? included original so that you can edit if wrong!
1711620893239.png1711620733855.png
 

Maglatron

Jul 12, 2023
1,454
Joined
Jul 12, 2023
Messages
1,454
need help with this one, I think like this1711625336784.png
1711621611426.png
 
Last edited:

bertus

Moderator
Nov 8, 2019
3,321
Joined
Nov 8, 2019
Messages
3,321
Hello,

Yes, if you follow those colors, you will have more overview over the signals.

Bertus
 

Maglatron

Jul 12, 2023
1,454
Joined
Jul 12, 2023
Messages
1,454
got a box pack of caps, can I use the electrolytic 100nF instead of the film ones?
 

bertus

Moderator
Nov 8, 2019
3,321
Joined
Nov 8, 2019
Messages
3,321
Hello,

Are you sure that the 100 nF capacitors are electrolytic?
If they are electolytic, I would not use them in the filters, but only for decoupling the power supplies.

Bertus
 

Maglatron

Jul 12, 2023
1,454
Joined
Jul 12, 2023
Messages
1,454
no the the 100nf caps I'm using are film type but I was just saying that I have electrolytic ones in the box I bought I do remember you saying that the 10uF ones on the REF GND circuit would be fine though!
 
Top