The Elenco
®
Burglar Alarm is designed to operate
from 9-15VDC. The electronic buzzer uses about
100 milliamps of current, so it is best to use an
alkaline battery to supply the necessary current.
The alkaline battery will last for about one hour of
continuous use. When connected to an automobile,
use the 12V car battery, as this will give almost
unlimited current. If an AC to DC power supply is
used, be sure that the supply can give 100mA at 9-
15 volts.
The silicon controlled rectifier is the heart of the
Burglar Alarm. This device is an electronic switch
that allows current to flow only in one direction.
Figure 1 shows a
simple circuit of an
SCR.
When a
positive voltage is
applied to the
anode and a
negative voltage to
the cathode,
no
current will flow.
INTRODUCTION
-2-
Figure 1
IDENTIFYING CAPACITOR VALUES
Capacitors will be identified by their capacitance value in pF (picofarads), nF (nanofarads), or
µ
F (microfarads).
Most capacitors will have their actual value printed on them. Some capacitors may have their value printed in
the following manner.
Second Digit
First Digit
Multiplier
Tolerance
The above value is 10 x 1,000 = 10,000pF or .01
µ
F
The letter K indicates a tolerance of +10%
The letter J indicates a tolerance of +5%
For the No.
0
1
2
3
4
5
8
9
Multiply By
1
10
100
1k
10k 100k .01
0.1
Multiplier
Note: The letter “R” may be used at times to
signify a decimal point; as in 3R3 = 3.3
1
0
µ
F
1
6
V
IDENTIFYING RESISTOR VALUES
Use the following information as a guide in properly identifying the value of resistors.
BAND 1
1st Digit
Color
Digit
Black
0
Brown
1
Red
2
Orange
3
Yellow
4
Green
5
Blue
6
Violet
7
Gray
8
White
9
BAND 2
2nd Digit
Color
Digit
Black
0
Brown
1
Red
2
Orange
3
Yellow
4
Green
5
Blue
6
Violet
7
Gray
8
White
9
Multiplier
Color
Multiplier
Black
1
Brown
10
Red
100
Orange
1,000
Yellow
10,000
Green
100,000
Blue
1,000,000
Silver
0.01
Gold
0.1
Resistance
Tolerance
Color
Tolerance
Silver
+10%
Gold
+5%
Brown
+1%
Red
+2%
Orange
+3%
Green
+.5%
Blue
+.25%
Violet
+.1%
Bands
1
2
Multiplier
Tolerance
103K
100
The Elenco
®
Burglar Alarm is designed to set off an
alarm whenever the circuit is activated. There are
two ways of activating the alarm; by opening a
contact switch and/or by shorting a contact switch.
Once the alarm is ON, returning the switch back to
its original position will not turn off the alarm. A third
switch controls the turn-off of the alarm. There is no
limit to the number of the switches that can be
placed to protect your property. You may use one for
each window and door in your house. There also is
a feature that allows use of the alarm to protect your
automobile and auto accessories.
POWER SUPPLY