Then start over with just a simple gain stage like in your first post, leave out the R and C filter.
Work on that until it amplifies with a gain of two times.
Work on that until it amplifies with a gain of two times.
this is the "more complicated one" but it doesnt have any type of unity gain. you could question the connection of the pin 1 with 3 and pin 7 with 5, its the only way it works not any other way. The loose wires are +,-, audio out. the connection on the positive rail on the top right is just so i dont loose it.
so i should add a 20 kohm resistor beetween the audio input and the ground? could i ask what this will do?
i dont see how it could fix my problem, is it possible if you give me a small explanation or a file where its explained i would like to learn why it could solve it.
You can remove the R1 and R2 and connect the output to the -input like shown in this tutorial
.. https://www.electronics-tutorials.ws/filter/filter_5.html
Then you have a unity gain active filter which buffers the input R and C.
You need to use short breadboard jumper wires especially if no input is connected. Oscillation is more likely with breadboards.
For debug, connect a dc voltage from a small battery to your input and/or use two resistors to divide one of your power supply voltages.
The output voltage should equal the +pin input voltage otherwise the circuit is broken.
.. https://www.electronics-tutorials.ws/filter/filter_5.html
Then you have a unity gain active filter which buffers the input R and C.
You need to use short breadboard jumper wires especially if no input is connected. Oscillation is more likely with breadboards.
For debug, connect a dc voltage from a small battery to your input and/or use two resistors to divide one of your power supply voltages.
The output voltage should equal the +pin input voltage otherwise the circuit is broken.
The problem by removing r1,r2 i start loosing input power as i can hear the overall loudness is alot less, if i do a unitt gain and just connect the output with -input the whole filter doesnt work anymore, but if i connect the output to the +input it works as it should (except for the gain).
Cant seem to understand why i should divide the powersupply voltage, cant i power it normally and put to the input a small battery to see the output voltage value?
Cant seem to understand why i should divide the powersupply voltage, cant i power it normally and put to the input a small battery to see the output voltage value?
Connect a pot between + and - supply pins. connect the center pin the +input of your opamp. Vary the pot around the center but not to the extremes. The output pin should follow the input voltage.
The tutorial I mentioned is conceptual and does not mention the opamp bias (but see post #3)
Take a look at https://sound-au.com/project11.htm. It has a different type of filter but shows a dual battery power suppy for example with general applicability. Mr Elliot is a good writer and makes an interesting site.
The tutorial I mentioned is conceptual and does not mention the opamp bias (but see post #3)
Take a look at https://sound-au.com/project11.htm. It has a different type of filter but shows a dual battery power suppy for example with general applicability. Mr Elliot is a good writer and makes an interesting site.
I understood, what would i achieve doing this? For example i put 1,5v on input and on my output there should be 1,5v and id there is for ex 1v my circuit isnt behaving as it should?
@Cpt.Prezzo .. what would i achieve doing this?
When you see that the output follows the input voltage you will know that the opamp is correctly connected to the power supply. Then you can investigate other problems. It is a process of elimination.
These plastic breadboards are popular for noisy digital arduinos and such. They are not so good for interesting analog audio.
Introduction https://sound-au.com/project41.htm
Opamps are wonderful little building blocks, but quickly building a test circuit is a real pain. Most people will use a 'breadboard', one of those plastic blocks with holes and connections, but I have found them to be a complete pain in the backside. After a while the contacts expand, wires fall out, and you can't actually see what you are doing anyway. One small slip, and the opamp is consigned to the dustbin.
...
When you see that the output follows the input voltage you will know that the opamp is correctly connected to the power supply. Then you can investigate other problems. It is a process of elimination.
These plastic breadboards are popular for noisy digital arduinos and such. They are not so good for interesting analog audio.
Introduction https://sound-au.com/project41.htm
Opamps are wonderful little building blocks, but quickly building a test circuit is a real pain. Most people will use a 'breadboard', one of those plastic blocks with holes and connections, but I have found them to be a complete pain in the backside. After a while the contacts expand, wires fall out, and you can't actually see what you are doing anyway. One small slip, and the opamp is consigned to the dustbin.
...
hello guys sorry for not saying nothing now i had free time, so i re-created the circuit making only a 1st order with a unity gain = 1 for simplicity. I tested what rayma suggested with a 22kohm resistor, it didnt work instead i found that doing a 1st order passive filter with a 90ohm resistor and 100uF capacitor is capable to remove any dc noise easily without having too much voltage trouble. After seeing that it works as supposed i made the gain factor of 1,586 (i know its wrong for a 1st order and is for a 2nd but i had the values on hand) and it does indeed work. Now im going to create the circuit as i wanted (4th order) im gonna eventually update if does or does not work. Thanks for everyone for the help/suggestions.
fubar3 i didnt try your suggestion for testing if it works as intended as i can hear that it does, i learned a new thing for testing. Thanks alot to you too.
UPDATE: so i tested for a 2nd order and it does not work (with the feedback of: "output-resistor-inverting in" and "inverting in-resistor-gnd") it does not work but if i short the pin 3 (non-inverting) with pin 1 (output) it does work. This behavour is only in 2nd order or more filter.
fubar3 i didnt try your suggestion for testing if it works as intended as i can hear that it does, i learned a new thing for testing. Thanks alot to you too.
UPDATE: so i tested for a 2nd order and it does not work (with the feedback of: "output-resistor-inverting in" and "inverting in-resistor-gnd") it does not work but if i short the pin 3 (non-inverting) with pin 1 (output) it does work. This behavour is only in 2nd order or more filter.
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well when it start working it works for 30 minutes and then again doesnt work for time. I dont have any other idea now
UPDATE: i did the circuit for the positive terminal to the negative terminal too (the resistor and capacitor) and now it works really good, only a little bit of noise but i think its because it is made like sh*t.
Again i want to thank you guys alot for the patience and help and for making me learn new useful things.
UPDATE: i did the circuit for the positive terminal to the negative terminal too (the resistor and capacitor) and now it works really good, only a little bit of noise but i think its because it is made like sh*t.
Again i want to thank you guys alot for the patience and help and for making me learn new useful things.
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