Current Sources Page

    Current sources

    Many applications require current sources rather than voltage sources. Current source provides a constant current to the output. This currentdoes not depend on the output voltage. An idea current source is a high output impedance device: it willsupply current, but does not show in other ways on the load circuit.When you need a low-current source, using a linear regulator isa typical approach. When you need a high-current source, using a linear regulator is inadvisable, because of the high power dissipation in the series resistor. To solve the wasted-power problem, you can use a switch-mode regulator. In some applications current signal sources are needed for measurement purposes. One very easy trick is to insert a large value resistor (compared to the impedance of the circuit measured) in series with the generator. This willessentially convert your constant voltage generator to a constantcurrent source. This is not completely ideal current source, butgood enough approximation for most applications, where the load resistance is much smaller than the current limiting resistor resistance.


Back to ePanorama main page ??