What if we want to clamp/clip current to a certain value or range as we do with diodes for voltage?
Here are a bunch of constant current circuits that I found while googling "contant current circuit: -




This is the classic use of a transistor - the load is in the
collector and you set the bias on the base so that there is a
certain voltage across R1 - if that voltage is 3.3V then, due to R1
being 3k3, no more than 1mA can be passed to the load.
If the LED (or load) tries to take more current than a certain value the lower NPN transistor starts to switch on the reduces the base voltage on the darlington thus current limiting is achieved.
This is the classic use of the LM317 regulator chip
This is a fairly simple and accurate current limit circuit. The voltage across R2 is held at (V+ -Vref) by action of the op-amp and transistor - this means the load (connected to the emitter) cannot draw more current than (V+ -Vref)/R2.
This is the same as (4) (sorry, my mistake)
This is very similar to (2) but works with a +V referenced load.
This is similar to (4) and (5) but uses a MOSFET as the current limiting element.


With voltage limiting the word clamping is often used. With current, the term used is often "limiting".