Elenco Space War Gun User Manual

SPACE WAR GUN KIT

MODEL K-10

Assembly and Instruction Manual

Copyright © 2010, 1989 by Elenco®Electronics, Inc. All rights reserved. Revised 2010 REV-J 753210A

No part of this book shall be reproduced by any means; electronic, photocopying, or otherwise without written permission from the publisher.

Elenco®Electronics, Inc.

CAPACITORS

Qty. Symbol Description Part #

r 2 C2, C3 .01μF Discap (103) 241031
r 1 C1 220μF Electrolytic 282244

SEMICONDUCTORS

Qty. Symbol Description Part #

r 1 IC1 LM556 Integrated Circuit 330556
r 1D1

LED (Light Emitting Diode) Red

350002

r 1D2

LED (Light Emitting Diode) Green

350010

MISCELLANEOUS

Qty. Symbol Description Part #

r 1 PC Board 518010
r 1 S1 Switch Push Button 540001
r 1 S2 Switch Slide 541102
r 1 B1 Battery Snap 9V 590098
r 1 SPK1 Speaker 8Ω 590102
r 1 IC Socket 14-pin 664014
r 2 Wire 4” Blue 814620

PARTS LIST

If you are a student, and any parts are missing or damaged, please see instructor or bookstore.
If you purchased this kit from a distributor, catalog, etc., please contact Elenco®Electronics (address/phone/e-mail
is at the back of this manual) for additional assistance, if needed. DO NOT contact your place of purchase as they
will not be able to help you.

RESISTORS

Qty. Symbol Description Color Code Part #

r 1R5 47Ω 5% 1/4W yellow-violet-black-gold 124700
r 2 R1, R2 100Ω 5% 1/4W brown-black-brown-gold 131000
r 1 R6 560Ω 5% 1/4W green-blue-brown-gold 135600
r 1R3 1kΩ 5% 1/4W brown-black-red-gold 141000
r 1 R4 56kΩ 5% 1/4W green-blue-orange-gold 155600
r 1 P1 Trim 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%

Note: The letter “R” may be used at times to signify a decimal
point; as in 3R3 = 3.3

IC Socket

Multiplier

For the No. 0 1 2 3 4 5 8 9

Multiply By 1 10 100 1k 10k

100k

.01 0.1

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.

Warning: If the capacitor is connected with
incorrect polarity, it may heat up and either
leak, or cause the capacitor to explode.

Polarity
Marking

-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 value 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