Converting 0-5V to 4-20mA using a Howland Current Pump for Scientists

  • Thread starter Thread starter DaineAtkins
  • Start date Start date
  • Tags Tags
    Industry Standard
Click For Summary
SUMMARY

This discussion focuses on converting a 0-5V signal to a 4-20mA output using a Howland Current Pump. The user seeks assistance due to misplaced notes and mentions using an LM741 operational amplifier. Key points include the need for a 250-ohm load and considerations regarding output impedance and voltage levels. A reference to a National Semiconductor application note titled "A Comprehensive Study of the Howland Current Pump" is provided for further insights.

PREREQUISITES
  • Understanding of Howland Current Pump design and operation
  • Familiarity with operational amplifiers, specifically the LM741
  • Knowledge of current and voltage conversion techniques
  • Basic circuit design and schematic creation skills
NEXT STEPS
  • Review the National Semiconductor application note on the Howland Current Pump
  • Study the principles of current-to-voltage conversion using operational amplifiers
  • Learn about output impedance considerations in analog circuits
  • Explore circuit simulation tools to design and test the Howland Current Pump
USEFUL FOR

Electronics engineers, circuit designers, and scientists involved in signal conversion and analog circuit design will benefit from this discussion.

DaineAtkins
Messages
3
Reaction score
0
I have a 0-5V signal which I need to convert 4-20mA by using a Howland Current pump.
I know that there are more steps to the whole process but I have misplaced all my notes that I originally had. Could someone please help?
 
Engineering news on Phys.org
Welcome to Physics Forums!

I fully admit that I've never heard of (or at least don't remember) the Howland Current Pump. However, the first Google Thing that comes up when Googling for Howland Current Pump:
http://www.google.ca/search?q=howland+current+pump

...is an app note from National Semiconductor entitled "A Comprehensive Study of the Howland Current Pump". Quickly perusing it, it seems to present a basic inspection analysis as well as a more detailed mathematical analysis (for both basic and improved variants).

Does this help?
 
The Howland Current Pump doesn't seem to be working properly.
Basically, I need to convert a 0-5V signal to 0-20mA
and a 1-5V signal to 4-20mA.
If anyone could please help me a.s.a.p!
 
Can you post your schematic, and your test methodology / results? Or are you asking us to design your circuit for you?

While we can't do the latter, we might be able to help you with the former.

If you're not worried about output impedance / voltage levels, and have (very) low input impedance (e.g. op-amp driven output driving an analog current meter) you could just use a 250 ohm resistor.
 
I am using a LM741 with an input of 5V and I need a 0-20mA output with a 250ohm load
I know that the saturation voltage of the op-amp is +/- 13V. I have calculated my design using a compliance voltage of 5V.
How do I post my schematic?
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
9K
  • · Replies 11 ·
Replies
11
Views
14K
Replies
8
Views
13K
  • · Replies 25 ·
Replies
25
Views
8K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
1
Views
2K
Replies
1
Views
908
  • · Replies 7 ·
Replies
7
Views
2K