How to test function of this circuit

Projects General Guidance
1

Hi. Wanted to asked on how to test this circuit. Its input stage of guitar pedal by electrosmash.
0f1d85041a48969efb558ee229a7c1c1

2

You could make it and see if it works. That is he only way to "test" it as such. You could run it in a simulator maybe??

3

I have it already built but i don't know what i am looking for.

1 Like
4

Who did you build it for? They will know how to use it. And they'll tell you if it doesn't work, I'd imagine.

5

Its just me :frowning:

6

How where you going to use it? Or was it made as a decoration? :grin:

Do you plan on using it? Do you know how to use one?

7

I want to make sure that this part of the cuircuit works. I know how the whole curcuit will work but i want to test this section and i dont know how. Do I mesure volts on input and output and then see if it amplifies ? OR how do i do it.

8

I've never built this,so I'm not sure. What voltage does it run at?

9

I guess 2.5 volts like shown in schematics

10

Can you please repost the schematic as a file? I want to download it and look at it closer.

1 Like
11

My guess: 5V connected to Vcc.
2.5V is a tap halfway...
Otherwise the +input of the comparator is at Vcc. Most opamps will not have a linear response then. Or may get damaged...

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12

pedalshield-uno-schematic
pedalshield-uno-schematic1920×1020 155 KB

Its the input stage block.

13

The pedal uses the +5V from Arduino Uno to feed the rail-to-rail operational amplifier and achieve design simplicity and maximum signal swing without clipping. divider R7&R8 generates 2.5V for virtual ground and the cap C6 remove ripple on the power line.

14

Cap C6 is upside down...

Do you have oscilloscope?

If so, plug in guitar and see what comes out...

Better would be:
Build an opamp circuit with zero output impedance to follow your output and connect that to headphones...

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15

Thanks. Avare of the C6 upside down. How do I build opamp circuit with zero output impedance. Can i look it up somewhere ? Is it require some changes in the circuits ? Sorry if its dumb question.

16 
           |\
Inp--------|+ \
           |    \___________outp
           |    /      |
        ---|- /        |
        |  |/          |
        |              |
        ----------------
17

Like this ?

image
image1382×723 89.1 KB

18

Does it look like my drawing?

19

I guess. I have never seen schematis drawn in text.

20

No, you have a lot more stuff than my drawing...
And your way it has positive feedback instead of negative feedback...