Elenco Burglar Alarm - Manual (Page 3)

The Elenco ® Burglar Alarm is designed to operate
from 9-15VDC. 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 µF (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 .01µF
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
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
Electrolytic capacitors have a positive and a negative
electrode. The negative lead is indicated on the
packaging by a stripe with minus signs and possibly
arrowheads. Also, the negative lead of a radial
electrolytic is shorter than the positive one.
Polarity
marking
(+)
(–)