The Component tester can be used with either the Philip Harris Puzzle Box or Component Investigations board to safely and quickly produce current and voltage characteristic curves for a number of electrical components. The component tester limits the voltage and current to safe values that will not damage any of the components and produces excellent results every time with minimal set up time. The component tester has connections for a Voltmeter and Ammeter and requires a 12V dc smoothed or regulated power supply.