Wide input range Amp

[ericgibbs]

I will need to Divide ADC /2.
Cheers.

hi,
The adc2 is divided by 2 using the resistive divider at the input of the first OPA, this reduces the signal input range to +/-5V at the OPA pin.

No additional division is required.

 

[camerart]

hi,
The adc2 is divided by 2 using the resistive divider at the input of the first OPA, this reduces the signal input range to +/-5V at the OPA pin.

No additional division is required.

Hi Eric,

Blimey! That's clever.

Cheers.

 

[camerart]

Hi Eric,

I've had an enforced break in my electronics, and I'm now trying to remind myself about your circuit.

Is it ok to re-start from where we left off and ask a few final questions, before I construct it?

Cheers.

 

[ericgibbs]

Hi Eric,

I've had an enforced break in my electronics, and I'm now trying to remind myself about your circuit.

Is it ok to re-start from where we left off and ask a few final questions, before I construct it?

Cheers.

hi,
Ready when you are.

 

[camerart]

Morning,

Is D3 is a 5.6V Zener Diode?

On the power supply, there are resistors on each pole Ip and In '0.01' Can you clarify please.

There are a couple of notes on the drawing. "use a jfet cc" What is a cc? and ".dc V2 tm 10 10m" also baffled me?

Cheers.

 

[ericgibbs]

Morning,

Is D3 is a 5.6V Zener Diode?

On the power supply, there are resistors on each pole Ip and In '0.01' Can you clarify please.

There are a couple of notes on the drawing. "use a jfet cc" What is a cc? and ".dc V2 tm 10 10m" also baffled me?

Cheers.

hi,
D3 is a 5.6V Zener
Ignore the Ip, 0.01, they are for simulation only.
Use a JFET CC, is a junction FET Constant Current sink
The .dc V2 etc...... is a simulation command, ignore it.

OK.?

 

[camerart]

hi,
D3 is a 5.6V Zener
Ignore the Ip, 0.01, they are for simulation only.
Use a JFET CC, is a junction FET Constant Current sink
The .dc V2 etc...... is a simulation command, ignore it.

OK.?

Hi Eric,

All fine thanks.

Cheers.

 

[alec_t]

Once set-up the signals normally don't vary too much (But can do)

So couldn't you simply use a pre-set pot at the input?

Alec

 

[camerart]

Hi alec_t,

1st I will make the full circuit as prescribed by Eric.

On the chip that reads the A/Ds, I have 2 A/D inputs, but for this I need 4, so I will need to make some changes.

What you suggest might be best, or perhaps a double switch or similar.

Thanks.

 

[camerart]

hi,
Question, do you want the 1mV thru 10V AC to be linear over the compression range required, ie: 0mVac = 0Vdc thru 10Vac = 5Vdc...??

Hi Eric,

Alec-t asked if it would be possible to simply use a POT immediately after the COIL around the first Opamp, then set the range between the two different circuits (1mv-1 and 1-10) each time.

In this early question of yours, you ask if I want linear? I was wondering if there is a way of adding components that give a none linear line, as my black line on your Graph (attached).

This would be a luxury, failing this, I'm more than happy with your original design.

Cheers.