Current Sink LM317 Layout
The current sink project aims to provide test for power supplies as well as obtaining the amount of current of an
LED.
The circuit automatically adjusts its effective resistance to maintain a constant current which is set by the voltage from a variable resistor. a
transistor can also be used as the adjustable resistance to maintain the current. An adjustable current sink can simulate a load at some set current and can be connected directly to a power supply output while adjusting the current to the desired level.
Current Sink LM317 Circuit
There are two possible circuits to build this current sink, one using a transistor as the primary component and another where an op-amp is included to overcome some minor issues. The transistor in each current sink circuit serves as the variable resistor that will pass the desired current. It is basically controller through its base to function as a resistor with whatever resistance needed to get the desired current to flow. The op-amp controlled current sink works well by outputting the necessary information to the base of the transistor to get the voltage drop. A LM317 comprises the
power supply along with a bridge rectifier.