Hello all
Could anybody help me with task.
I have two sinusoidal signals, phases difference is 90 degrees, frequency about 500kHz, wires from source of signal to PCB are about 15 cm. Amplitude of signals are about 300mV.
I have to use operational amplifiers to get the output 1V. Phase difference should be the same after amplification.
P.s. I have prototyping PCB, and I am going to buy some OpAmp in DIP case.

 

Show your work, and tell us what you are stuck on.

 

A plastic, plug-in, practice board is going to give you trouble with stray capacitance at 500 KHz. I hope, "prototyping PCB" means copper traces and solder.

 

A plastic, plug-in, practice board is going to give you trouble with stray capacitance at 500 KHz. I hope, "prototyping PCB" means copper traces and solder.

if I change frequency to 100 kHz?
And what i need to do if i have Power Supply with only +5V, without -5V.

that's what I got in the simulator

 

if I change frequency to 100 kHz?
And what i need to do if i have Power Supply with only +5V, without -5V.

that's what I got in the simulator

How much gain does your amplifier need? How much do you have in your simulation?
Show us calculations. Anyone can use a simulator.

 

Op-Amps seem like overkill.
You could do the same with a single stage transistor amplifier.
If you use common emitter stages the output will be inverted but they will still be 90 degrees apart (in quadrature to each other)

You could also use common base amplifiers if your source can handle a low impedance load.

 

Op-Amps seem like overkill.
You could do the same with a single stage transistor amplifier.
If you use common emitter stages the output will be inverted but they will still be 90 degrees apart (in quadrature to each other)

You could also use common base amplifiers if your source can handle a low impedance load.

Hi Sue,great to see you on this forum.
Your commonsense approach to Electronics will go over well here!

73,VK6ZGO

 

Op-Amps seem like overkill.
You could do the same with a single stage transistor amplifier.
If you use common emitter stages the output will be inverted but they will still be 90 degrees apart (in quadrature to each other)

You could also use common base amplifiers if your source can handle a low impedance load.

This is the homework forum. The OP said

I have to use operational amplifiers

.
I assumed this was part of the assignment.

 

How much gain does your amplifier need? How much do you have in your simulation?
Show us calculations. Anyone can use a simulator.

If 300mV need increase to 1V. I think, gain must be about 3.3.

I made new simulations.

With MCP601 (rail to rail OP-amp)

In case 1.jpg, 1s.jpg, I tried to make a differential amplifier at 3 OP-amp.

In case 2.jpg, 2s.jpg I tried to make a differential amplifier at 3 OP-amp.

Please advise me which case is better, and where will be better use Adjustable resistors for adjust gain.

All resistors in both cases were selected randomly. I just picked them up to get the desired gain.

 

You are correct about the gain. Your circuits are unnecessarily complicated. You don't need a differential amplifier.

1. Have you been taught feedback theory, and/or op amp circuits?

2. Do you know anything about the signal source? What is the source impedance, or what is the signal coming from?

3. Are the two signals separate, or are they combined on the same wire?

Please answer ALL the questions.

 

You are correct about the gain. Your circuits are unnecessarily complicated. You don't need a differential amplifier.

1. Have you been taught feedback theory, and/or op amp circuits?

2. Do you know anything about the signal source? What is the source impedance, or what is the signal coming from?

3. Are the two signals separate, or are they combined on the same wire?

Please answer ALL the questions.

1.Yes
2.Source of signals is phototransistor, but i don't know kind of it, and don't know impedance.
3. Actually i have four wire, 1 and 2 sinusoidal signal and inverse sinusoidal signal, 3 and 4 sinusoidal signal and inverse sinusoidal signal.

I'd like use diff. op. amp because I want to avoid interference

 

When you say "inverse sinudoidal signal", do you mean that if you measure between that line and ground that you see a sinusoid? Or do you just mean that it is the return wire for that signal?

If the former, is your 300mV the peak value of the sinusoid on either line, or the peak value of the difference between the two lines?

 

When you say "inverse sinudoidal signal", do you mean that if you measure between that line and ground that you see a sinusoid? Or do you just mean that it is the return wire for that signal?

If the former, is your 300mV the peak value of the sinusoid on either line, or the peak value of the difference between the two lines?

I mean measure between line and ground. 300mV is peak value of sinusoid on either line.

 

So you have 600mV peak value between them?

And what are you wanting for an output? A singal-ended output in which you have a 1V amplitude signal relative to ground? Or a differential output in which you have a 1V amplitude signal between the two outputs? Or what?

 

So you have 600mV peak value between them?

And what are you wanting for an output? A singal-ended output in which you have a 1V amplitude signal relative to ground? Or a differential output in which you have a 1V amplitude signal between the two outputs? Or what?

Sorry, i have 300mV peak.

I'd like will get 1V amplitude signal relative to ground.

 

This is the homework forum. The OP said .
I assumed this was part of the assignment.

I'll have to pay more attention to the forums I post in...
Sorry.

 

I'll have to pay more attention to the forums I post in...
Sorry.

It's the kind of mistake that if we haven't made it, will will. And if we have made it, we will make it again.