Yes, there are "electric" and mechanical gauges.(talking aftermarket here)Mechanical use capillary tubes or small tubing for the oil pressure and temp. gauges, while electrical have sending units mounted on the engine and electric wires into the interior. Electrical ,particularly for oil is safer. With mechanical, oil is inside the car, and if the line leaks, lots of flammable oil enters the interior.
As for monitoring your electrical system, a voltmeter provides better info and is safer than an ammeter.An ammeter has large amounts of current running through it.
I prefer "electrical" type oil press and temp gauges and a voltmeter rather than an ammeter.
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