Hi!
I am new to electronics and wanted to ask for help with this circuit. I am trying to simulate peak follower in LT spice. I came up with something like this but I don't know why I can't measure voltage on the output when I run the calculation, as if there were no voltage there. In my opinion there should be, that's why I am asking, maybe you could help me find what am I doing wrong?

 

Post you .asc file.

Note that a 741 output will only go to about 3V peak with a 5V supply.

 

hi, T,
You have a short circuit!
E

 

Talk about clamping the output!

 

hi, T,
You have a short circuit!
E
View attachment 334445

thank you thank you thank you thank youuuu!!

 

I am trying to simulate peak follower in LT spice.

In addition to the short, you've drawn the circuit backwards and have too much whitespace. Flow should be predominantly left-to-right and top-to-bottom and ground should point down. Also, LM741 don't operate well from such low supply values.

 

Can you tell me then how could I improve on this circuit? What components to explore, how to even calculate right values for components, also was wondering if there is a way to simulate audio signal in LTSPICE (that is uneven in amplitudes). Maybe you know if there is some good source for people like me that is worth it to dive deeper in? Or maybe it's okay if I struggle with something to post questions here on forum?

 

also was wondering if there is a way to simulate audio signal in LTSPICE (that is uneven in amplitudes).

Select PWL file in a voltage source and supply a file having time and voltage data. You could convert an audio sample file to what it wants.

 

Select PWL file in a voltage source and supply a file having time and voltage data. You could convert an audio sample file to what it wants.

I've got it, it works. I used ctrl + right click with mouse on the voltage source and then I typed in value space wavefile=[name of my file].wav
thanks

 

Okay so, I am not at home yet. Now I've got some peaks but these are centralised around 1.37 V, and are oscillating beetwen really small values. Green is voltage on resistor, blue is voltage at source. It's really weird because waveform is preserved by cap, but amplitudes are not. I assume th issue may lie in opamp but I think it is connected alright.

 

Hello,

Do you really intend to use the LM741?
Try a higher supply voltage of 5 to 15 volts for the LM741.

Bertus

 

Hello,

Do you really intend to use the LM741?
Try a higher supply voltage of 5 to 15 volts for the LM741.

Bertus

No I just pasted random opamp from internet. Which one would you recommend? Why not this exact one?

 

That exact one is very old tech and has a lot of limitations that newer ones don't. For example, it is intended for a much higher supply voltage since the output cannot get very close to the supply - at 5 volts there is very little operating width.

Personally I have a heap of LMC6482 so that's what I use.

 

Which one would you recommend?

The 741 is an ancient device developed in 1968, that was the first IC op amp with built-in compensation.
It has rather poor specs in most categories as compared to modern op amp designs.

I like the low-cost TLV915x op amp which comes in a single, dual, or quad package.
It is a CMOS rail-rail input/output device with near zero input current, lower input offset voltage and noise, and higher gain-bandwidth and slew-rate than most common general-purpose types.
For many typical applications it has near ideal characteristics.