red led with 9 V battery connected via breadboard and coin

by mathias_magdowski - uploaded on October 21, 2018, 8:00 pm

This is a plain red light-emitting diode with 5 mm diameter and straight wire connectors powered by a 9 V battery using a battery clip and a breadboard for connection. Please note that this only works, if the led features some internal series resistor to limit the forward current. The circuit is closed via two red wires and a metal coin. Using this circuit, other things as the coin can be tested for their conductivity for electric current.