voltage to current converter

[nitskulkarni]

I want to convert a 0V to 150V dc voltage to 4 to 20mA current
please help me

 

[stevez]

Do you really want zero volts? A 5k resistor across 150 volts results in 30 ma - 4 ma at 20 volts - so with a simple resistor you can get 20 volts to 150 volts to result in current flow of 4 ma to 30 ma.

 

[nitskulkarni]

sorry but i wrote it wrong the o/p current should be 4-20mA
yes I want the i/p voltage from 0 to 150V
Its actually an exam question on OPAMPs

 

[crutschow]

You need an op amp configured as a voltage input to current output converter. A Google search should give you some ideas on that. (Hint: Using a transistor at the output simplifies the circuit). You bias it to give 4mA output with 0V input. Then you adjust the gain to give you an additional 16mA with 150V input.

 

[Diver300]

Is the 4 - 20 mA loop powered? If not, what power supply have you got?

Is this what want?
https://www.spinix.com/dcvt420.pdf