IC required for the following requirement - please can anybody help?

[nagarjun9995]

Hello Everyone,


I am designing a circuit for my academic project.

I am urgently in need of a IC for a Current controlled Oscillator (CCO) for the range 4-20mA

and a IC for a voltage controlled oscillator (VCO) for the range 0-10V with frequency range 0-50Hz.

Please can you help me in finding the IC's for the above and assist me.


Thank You in advance.

 

[BradtheRad]

I devised this V to F converter based on an op amp and transistor.

It gives linear performance within a few percent, over the entire range of operation.



There is a threshold for detection, which is the lowest you can go and still get oscillations. This threshold is about two tenths of a volt.

You can tailor adjust the 12k resistor until it yields 50 Hz with a 10V input.

 

[nagarjun9995]

Hello BradtheRad,

Your post is really helpful for me and I am thankful to you.

What is the least input value of voltage and the least output frequency in the above circuit?

Thank you.

 

[BradtheRad]

Looking at my notes when I constructed this years ago...
It appears I managed to detect as low as .02 V.

I've persuaded the simulation to resemble something closer to that.



It is important to get the capacitor waveform adjusted, so it is just above the zero line.

Supposedly you can expect an input of .02 V to yield 0.1 Hz. In reality it will be slightly less, because the capacitor charges more slowly, and becomes more gradual as it reaches a plateau.

When the input goes below 0.02 V, the output is flat.

(Don't know how my post appeared in triplicate.)

 

[keith1200rs]

(Don't know how my post appeared in triplicate.)

It a s forum software bug which happens from time to time. If I deleted one, the other two would also disappear. It is a mystery!

Keith