I am just not sure that why in development labs, current sources are not as popular as voltage sources.

I have worked in different places, and they all have been using voltage sources.

I just want to find out why, in practice, voltage sources are much more popular than current sources. And, if there are applications that current sources are actually being used instead. And what are the main advantages/disadvantages of using one vs. the other.

  • 1
    \$\begingroup\$ A safety note: Some current sources can be quite a bit more dangerous than voltage sources. They will increase voltage as far as needed to keep the current constant. Not many, but some. A similar device is the constant power source used in electrophoresis. They have a lid and a safety switch because you couldn't design a better electrocution device. \$\endgroup\$ – C. Towne Springer Jan 4 '14 at 0:44
  • \$\begingroup\$ An ideal voltage source will supply an infinite current if you short circuit it. An ideal current source, when disconnected from any load, will create an immense plasma fireball that will chase you down the lab and consume the building. Fortunately, real world devices are somewhat more wimpy. But real world sources such as batteries better approximated voltage sources so we have become more used to them. ... \$\endgroup\$ – Russell McMahon Jan 4 '14 at 4:16
  • \$\begingroup\$ ... An open circuit real world current source will always sit at its maximum allowed Vout and is "potentially" [groan] more dangerous. Both are useful. LEDs should be operated from current sources as they are better thought of as current rather than voltage driven. / ... \$\endgroup\$ – Russell McMahon Jan 4 '14 at 4:16

There are no advantages or disadvantages. Some devices require constant voltage. Some devices require constant current.

Majority of the DUTs** require constant voltage. That's why most of the bench top power supplies, which you have encountered in the labs, are constant voltage. Keep in mind that a descent lab power supplies have and adjustable max current threshold and 2 modes: constant voltage (CV) and constant current (CC). CC mode is activated automatically, when the DUT tries to pull more than the max current. Often, it's a sign of a problem, when a DUT wants to pull more current than expected.

Few DUTs require constant current. LEDs, for example. Often, a constant voltage supply powers a separate constant current circuit, which in turn powers a constant current DUT.

** DUT - device under test

  • 2
    \$\begingroup\$ Note that the current limiting functionality of power supplies may not be the same as constant current in power supplies that apply a current foldback method \$\endgroup\$ – alexan_e Jan 4 '14 at 0:50

There are no Advantages or Disadvantages as indicated by Norton or thevenin equivalent circuit .

As for the popularity voltage sources are more easily available to people so they do not even bother to try out the current source in their work since it would not make any difference

About the last part ,"The applications" : http://www.ti.com/lit/an/sboa046/sboa046.pdf


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.