Riffling through my box of old projects, I came upon a project that I had built in the 80’s — an Automotive Multimeter which was published in the Dutch/British Elektor magazine. It could measure low voltage DC, high current DC, resistance, dwell angle, and engine RPM and ran off a single 9V battery. Besides a 555 IC for the dwell and RPM measurement and a couple of CMOS gate chips, the rest of the board is populated by a smattering of passives and a big, 40 pin DIP IC under the 3½ digit LCD display. I dug some more in …read more
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