The 741 op amp has a rugged design with a short circuit protection feature if any one could shed the light on this mechanism where I have found it to be on of the most power efficient protection circuits that would not drain the power of a battery. I would really appreciate it and thank you in advance for you efforts!
1 Answer
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If you look at the circuit diagram of a 741
you will see this at the top of the output stage...
The output path is through Q14 and R6. When the current though R6 is high enough it turns on Q15 which starts to turn off Q14. This limits the amount of current it can ever source to about ~0.6V/27R = ~20mA.
It is your basic current limiter circuit.
A similar circuit, PNP version, exits below that to limit the sink current.
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1\$\begingroup\$ I do something similar for resolver excitation circuits to ensure they are short-circuit protected \$\endgroup\$– user16222Commented Oct 27, 2017 at 17:16