Electronics, PCB Design and PCB Layout Daycounter, Inc.
Engineering Services

Custom Firmware, Electronics Design, and PCB Layout

                 
 
Electronics Design
Firmware Development
Software Development
Embedded Design
PCB Layout
Digital Signal Processing (DSP)
Reverse Engineering
Prototyping
Device Driver Development
VHDL
Motor Controllers
Microcontrollers
Data Acquisition Systems
Palm OS Software
Windows CE Software
Pocket PC Software
Design for Manufacturing
Through Hole to Surface Mount (SMT) Conversion 
Microchip PIC Consultant
MSP430 Development
DSP56 Development
RoHs Redesign
Design for USB



Silver Board Contract Assembly


 

Voltage Controlled Current Source - Current Servo

See our other Circuits.

This circuit allows a current device to be controlled with a small control voltage.  The op-amp loop forces the output current to be proportional to the control voltage VC.

The current to the controlled device is equal to the current through R3, the current sense resistor. The currents through R1 and R2 are essentially zero, so we can neglect their voltage drops in the circuit. The op-amp's negative feedback will adjust the current through the MOSFET until the voltage across R3 is equal to the control voltage.   Thus, the voltage across R3 is equal to the control voltage VC. 

IR3= VC/R3

The control voltage should be limited such that the maximum current of the controlled device is not exceeded. Typically, the voltage is a few hundred milivolts. C1 provides some low pass filtering of the feedback.

 

 

Do you need help with an electronics design?  Daycounter provides contract electronics design services. Contact us to give you a quote on your electronics design project.

 

[Employment] [Downloads] [Articles] [Contact Us]

Salt Lake City, UT, USA

Disclaimer: Daycounter, Inc. doesn't guarantee the accuracy of any of it's content. Use at your own risk.

© Copyright 2016 Daycounter, Inc. All rights Reserved.






Soil Moisture Sensor Probe



Water Level Sensor