Elenco Electronics K-10 Assembly And Instruction Manual
SPACE WAR GUN KIT
MODEL K-10
Assembly and Instruction Manual
Elenco Electronics, Inc.
Copyright © 1989 Elenco Electronics, Inc. Revised 2001 REV-H 753210A
CAPACITORS
Qty Symbol Description Part #
2 C2, C3 .01µF Discap (103) 241031
1 C1 220µF Electrolytic 282244
SEMICONDUCTORS
Qty Symbol Description Part #
1 IC1 LM556 Integrated Circuit 330556
1D1
LED (Light Emitting Diode) Red
350002
1D2
LED (Light Emitting Diode) Green
350010
MISCELLANEOUS
Qty Symbol Description Part #
1 PC Board 518010
1 S1 Switch Push Button 540001
1 S2 Switch Slide 541102
1 Solder Roll 24” 551124
1 B1 Batter y Snap 9V 590098
1 SPK1 Speaker 8Ω 590102
1 IC Socket 14-pin 664014
2 Wire 4” Blue 814620
PARTS LIST
Contact Elenco Electronics (address/phone/e-mail is at the back of this manual) if any parts are missing or
damaged. DO NOT contact your place of purchase as they will not be able to help you.
RESISTORS
Qty Symbol Description Color Code Part #
1R5 47Ω 5% 1/4W yellow-violet-black-gold 124700
2 R1, R2 100Ω 5% 1/4W brown-black-brown-gold 131000
1 R6 560Ω 5% 1/4W green-blue-brown-gold 135600
1R3 1kΩ 5% 1/4W brown-black-red-gold 141000
1 R4 56kΩ 5% 1/4W green-blue-orange-gold 155600
1 P1 Tr im Pot 50kΩ 191552
-1-
Resistor Transistor
Capacitor
Push Button
PARTS IDENTIFICATION
Electrolytic
Speaker
Integrated Circuit
Switch
Discap
LED
Trim Pot
Battery Snap
IDENTIFYING RESISTOR VALUES
Use the following information as a guide in properly
identifying the value of resistors.
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. 01234589
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
IC Socket
-2-
CIRCUIT OPERATION
Figure 1 shows the circuit of the Space War
Gun. It consists of two 555 integrated circuits
(IC) packaged in one IC 556. A 555 timer is well
known for its ability to operate as an astable
multivibrator oscillator. This oscillator can put
out a square wave or pulses depending on the
value of the resistors. The first 555A IC
oscillates at about 2000 cycles per second. The
555A IC drives the 555B IC to give the weird
space sounds.
THE 555 IC TIMER
Let’s study the right side of Figure 1 which shows the 555B circuit. Resistor R3, R4 and
capacitor C3 control the frequency of oscillation of this circuit. Capacitor C3 charges
through resistors R3 and R4, but discharges through resistor R4 and the IC. Since the
value of R3 and R4 are 1kΩ and 56kΩ respectively, their total value equals 57kΩ. Thus,
C3 charges through 57kΩ and discharges through 56kΩ. The charge and discharge time
is about equal. The output at pin 5 will be a square wave as shown in Figure 2. The
frequency of oscillation will be around 2,000 cycles per second. If a speaker is connected
to output pin 5, we will hear the 2,000 cycle tone. When the two LEDs are connected to
this output, they will light whenever the output goes positive. Resistor R6 is added to limit
the current in the LEDs. Resistor R5 is added to limit the current in the speaker.
The operation of the 555A IC differs quite a bit from the 555B IC . Note the v alue of the capacitor C1, it is 220µF
or 22,000 times bigger than the .01µF used in the 555B. This means that the frequency of oscillation will be
much lower. Also, resistor P1 is made a 50,000Ω variable. Resistor R2 is only 100Ω. Thus, the charge time
on capacitor C1 is through the 100Ω. With the pot at the maximum position, the charge to discharge will be
500:1. Figure 3A shows the pulse as it appears in
the output in 9. Figure 3B shows the voltage across
capacitor C1. By varying the value of P1, the
distance between the pulses will be made shorter of
the frequency will be increased. At the minimum
position, the charge time will be twice the discharge
time (200Ω versus 100Ω). Thus, varying P1 will
change the frequency between .1 cycles to 45
cycles. This change in frequency adds to the effects
of the Space War Gun.
VOLTAGE CONTROLLED OSCILLATOR (VCO)
The 555 timer is designed to allow the output frequency to be varied by changing the DC voltage. If we raise
the voltage at the 555B input pin 3, the output will decrease in frequency. In the Space Gun design, the VCO
of the 555B is connected to the voltage across capacitor C1. This voltage is sawtooth in shape as shown in
Figure 3B. As this voltage increases, the pitch-frequency of the 555B timer is constantly changing at a rate
determined by the voltage amplitude of the 555A timer.
Figure 2
Figure 3B
Figure 3A
Clock Circuit
555
Output
5
Low
R1
S1
P1
S2
R2
8
13
C1
B1
9V
12
7
11
C2
555A 555B
410
9
N.C.
R4
C3
2
7
6
1
R3
14510
R5
R6
D1
D2
3
SPK
+
Figure 1
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