i would like to seek your expertise once more, this time with the voltage to current converter. I have attached a circuit which resembles the voltage to current circuit i am working with now.

i cannot interpret the formula that was used in obtaining the equivalent ampere.

I = (frequency input * 0.0008mA + 4 mA)

whereas

frequency input = Vinput/0.0005

i cannot obtain the or multiplier 0.0008 or even that data 4 mA that ws added to the bove equation.

How they obtained this formula.....

The value of the zener above is 2.495 V with Ik = 10mA.

Is that a reference for the circuit??? How could i obtain the output if that is true...

Additional data:

for frequency ranging 200 - 20000 Hz, the value of current output that could be obtained is 4.16mA - 20 mA, that is for 20kHz, you got a 20 mA. please help me explain the other part of the circuit..... similarly, 200 - 20000 Hz is equivalent to 0.1 to 10 V... thanks, i would appreciate your help...