Data Sheet

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17. Electronic Efciency

Electronic Efciency is dened as the Useful Power Output

divided by the Total Power Input.

Build the circuit to the left and press the switch (62). The

LED (69) will light, but the lamp (76) will not light. There is

resistance built into the LED (69) to protect it (too much

current could damage an LED), and this resistance is limiting

the current in the circuit. Yet this circuit shows that the

LED (69) is more efcient than the lamp (76) because it still

produces light (useful output power) even at the lower current.

18. House Wiring

Build the circuit to the left. Turn ON the

switch (62) and the LED (69), the lamp (76),

and the motor (95) will all be on at the same

time. In this circuit the LED (69), the lamp

(76), and the motor (95) are in parallel.

Pretend the LED is a television, the motor is

a ceiling fan, and the lamp is a house lamp on

an end table. Just like in your home, you can

turn any one of these OFF by removing them

from the circuit and the rest will stay ON.

This demonstrates why your house wiring

uses parallel circuits and not series circuits.

1st level

2nd level