Application Circuit of LM1042 in the Car

Application Circuit ofLM1042in the car as shown. Power from the +12 V battery. The oil pressure switch S1 to select the probe. S1 is closed, in the ignition of the car 8 feet by the wind will pull into a low, select the level in the probe a measuring tank. S1 after the engine began to work disconnected, U + after VD1 8-pin pull-high, change the measurement level by the auxiliary probe 2. Even if the engine stall, C5, 8-pin remains high, be able to prohibit the probe to a measurement. HL is the oil pressure warning lights. The VD2 prevent reverse polarity power supply. RP1 is used to adjust the probe current, I = 200mA. RP2 used to calibrate the duration of each measurement. Closure of S2, the COSC is shorted, select a single measurement mode. Disconnect S2 to repeat the measurement mode. For changing the voltage gain of the A4 along the dotted line in Fig. Access resistor R7. Digital voltmeter connected to the between Uo2 side and Uo1 of using R5, C6 can filter out the high-frequency interference of the instrument input.
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