Constant current source circuit problems
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This post was last edited by cnooczhouyx on 2013-1-24 at 13:11. In transistor amplification circuits, a constant current source circuit is generally used to suppress zero-point drift; please discuss the working principle of the constant current source circuit
A constant current source circuit is designed to provide a stable current, which serves as the basis for ensuring the stable operation of other circuits. That is, it requires the current source circuit to output a constant current; therefore, the device used as the output stage should have a voltage-current characteristic with a saturated output current. This can be achieved using a BJT or MOSFET operating in output current saturation mode. To ensure stable current in the output transistor, two conditions must be met: a) its input voltage must be stable—the input stage needs to be a constant-voltage source ； b) The output resistance of the output transistor should be as large as possible (ideally infinite) – the output stage needs to act as a constant current source.
Are all AO cards constant-current output sources?