Manual

-95-
Y
ou know that an LED promptly lights when you turn
it on. You can also light it up gradually. In this
p
roject, you’ll be able to observe the LEDs slowly
get brighter while you hold down the key.
This circuit arrangement is called a Miller integrating
circuit. The output of the circuit increases as its
input rises. The integrating circuit increases the
value of the 100mF capacitor above its actual value.
When you press the key, the LEDs become brighter
and the capacitor charges slowly through resistor R.
Setting the switch to position B discharges the
capacitor, and the LEDs turn off.
Before completing the project, set the switch to
position B, to discharge the capacitor. Set the switch
to position B and hold the key down to watch LEDs
1, 2, and 3 become brighter. In about 5 seconds
they will reach maximum brightness. Now set the
switch to B to discharge the capacitor, then hold
down the key to do the experiment again.
N
otes:
EXPERIMENT #76: MILLER INTEGRATING CIRCUIT
Schematic
Wiring Sequence:
o 31-63-122-137
o 32-34
o 35-37
o 38-72
o 71-67-116-133
o 68-90-115-132
o 69-124-119
o 70-121
o 89-138
EP-130_62315RevC.qxp_EP-130_062812 6/23/15 11:17 AM Page 95