User Guide

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Project #102
OBJECTIVE: To show the increase in voltage when batteries are
connected in series.
When you turn on the slide switch (S1), current flows from the
batteries through the slide switch, the 100Ω resistor (R1), the LED
(D1), through the LED (D2), and back to the second group of batteries
(B1). Notice how both LED’s are lit. The voltage is high enough to turn
on both LED’s when the batteries are connected in series. If only one
set of batteries is used, the LED’s will not light up.
Some devices use only one 1.5 volt battery, but they make hundreds
of volts electronically from this small source. A flash camera is an
example of this.
Batteries in Series
Project #103
OBJECTIVE: To show how batteries in parallel are used to
increase current.
Build the circuit shown on the left by placing all the parts with a black
1 next to them on the board first (including the 1-snap wire at base grid
location C6). Then, assemble the parts marked with a 2. Finally, place
the slide switch (S1) on top as shown. Leave the switch in the off
position.
The light should be on and the brightness of the lamp (L1) will depend
on the quality of the batteries in the holder (B1) on the left. Put weak
batteries in the left holder and strong batteries in the right holder. Now
turn on the switch. The lamp will get brighter as the fresh batteries
take over and supply the current to the light.
Batteries are placed in parallel when the voltage is high enough but
the circuit needs more current than one group of batteries can supply.
Think of each battery as a storage tank that supplies water. If you put
two in parallel, you can get more water (current), but the pressure
(voltage) stays the same.
Batteries in Parallel