With the bridge rectifier, you have two unnecessary diode drops. ?So a 12v battery might only deliver 10.5 volts or so to the rig.
The diode and fuse trick avoids the voltage drop, but is a rather brutal approach.
The LM2940* simply shuts down if battery is reversed with no voltage drop penalty, and provides over-voltage protection as well.
Jerry
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On Sun, Jun 11, 2017 at 05:25 pm, Dr Fred Hambrecht wrote:
Even better go through a fuse and have a standard diode between the fuse output and ground. If reversed the diode causes the fuse to blow. Another cure is to feed the input to a bridge rectifier and now it doesn¡¯t matter how you hook it up. I tend to use the bridge approach as the fuse seems to be blow right after the most expensive component in a circuit.
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