Elenco Circuit Maker Sound Plus 200 - Manual (Page 29)

-28-
Project #43
Change the 1KW resistor (R2) to the
5.1KW resistor (R3). Now the LED (D1)
is dimmer but stays on longer.
Project #44
Slower Off
Switch
Build the circuit, turn on the slide switch
(S1), and press the press switch (S2). You
see that the LED (D1) doesn’t turn off
immediately after you release the switch. If
you remove the capacitor from the circuit by
turning off the slide switch, then the LED
goes off immediately.
This delay in turning off the LED is caused
by the 100mF capacitor (C4). Capacitors
can store electricity and are used to delay
changes in voltage. They can block
unchanging voltages while passing fast-
changing voltages.
Slow Off Switch
Project #45
Current Control Q1
Project #46
Current Control Q2
Turn on the slide switch (S1), the LED (D1) and lamp (L4) are bright. This is an
unusual circuit which uses the PNP transistor (Q1) as two connected diodes to split
the current from the batteries (B3) into the paths with the LED and lamp.
This circuit is just like
the preceding one but it
uses the NPN
transistor (Q2). The
transistor connections
are opposite to the
NPN transistor (Q2),
but otherwise the circuit
works the same way.
Transistors use a small current to control a
large current, and have three connection
points (the small current, the larger current,
and the combined current). But they are
actually constructed using two diodes that
are connected together. These diodes are
similar to your LED (light emitting diode)
except that they don’t emit light.
CM-200_Manual_031914.qxp_CM-200_Manual_031914 4/2/14 12:04 PM Page 29