I have been experimenting with simulating current limiting circuits. I am trying to limit current to ~500mA given a fixed 4.8V source. I started a question based on a conventional 2-transistor current limiting circuit over here based on the following schematic . . .
Rather than make that question more convoluted, I thought I would ask a separate question to determine what the difference is between the above circuit, and another variety that I found commonly using google image search that involve use of diodes. The 1-transistor variant of these looks like the following . . .
Then there is a circuit with another transistor added
... and finally there is a circuit that looks like a similar configuration using 3 transistors . .
What are the differences between these diode based circuits and what are their advantages/disadvantages compared to the current limiter shown at the top of the page?