Electronics Circuit Diagram

Car Battery Tester Circuit Design using LM3914. To check a battery surface voltage, remove the positive terminal protective cover. Connect the +positive side meter lead (red) to the positive side battery terminal.

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The following schematic shows the design of a Simple Voltage Tester Circuit Diagram and its electronic components/parts list. You can use this circuit design to test voltage, transformers, speakers, as well as microphones.
Simple Voltage Tester Components/Parts List:
R1 = 5.6M
R2 = 1.8R
R3 = 15R

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The following schematic shows a LED Tester Circuit Diagram. This LED tester circuit design consists of a current source (TL081 Opamp) with a potentiometer. You can use the tester to test LEDs that are in engines or on wire leads by clipping test leads to wires or LED leads that are inserted into the holes.

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