Data Sheet

-23-

15. Electrical Current Indicators

Build the circuit to the left and turn ON with switch (62). Both

the lamp (76) and the LED (69) will light up. This demonstrates

that electrical current is owing through both parts. Turn OFF

the power and turn both the lamp (76) and LED (69) around.

Turn ON the switch (62) and the LED (69) will be OFF but the

lamp (76) will be ON. This demonstrates that current is only

owing through the lamp. The lamp (76) and the LED (69)

are very simple devices that can be used to detect current

ow. A more advanced device, called an ammeter, is used to

measure the amount of electrical current owing in a circuit.

16. Power ‘ON’ Indicator

Build the circuit to the left. Press the switch (62), the LED (69)

will light up and the motor (95) will start spinning. Without

the fan blade it is difcult to see if the motor is ‘ON’ when

far from the circuit. With the LED in parallel with the motor,

a visual indicator that the motor is ‘ON’ can be seen from a

distance. Red LEDs are often used on electrical devices to

show they are ‘ON’. Wasted “Watts” cost money and is bad

for the environment.

1st level

Level block