Star Tech Journal

STAR*TECH JOURNAL/NOVEMBER 1983
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The names of various Laser Disc Optics
comprise this issue's word puzzle. Find and
encircle these words as they appear below.
They run vertically, horizontally, diagonally
and sometimes backwards.
25
66. The distinguishing feature and principal advantage of thyristors is that
a. they are the only high-power semiconductor switching devices available.
b. their switching speed is faster than that of most transistors.
c. they are typically less expensive than transistors.
d they are easy to tum off by means of control current at the gate.
e. only a quick, momentary pulse of gate current is required to tum them on all
the way ( so that less power is wasted in the control circuit than with a
transistor).
67. Which of the schematic symbols shown is that of the SCR ( silicon controlled
rectifier, also called "reverse-blocking triode thyristor")?
MT 2
a.
LASER DISC OPTICS
GATE
M E Q B O N C D Q R
I Q O N W I V O U U
RXPSDFZIWT
R N V E A P Z
Q
E Z
0 B Y H B F M U V G
R S X V E A N R A C
G I N X F P R I W F
T R I E A S W I R U
0 R A J L X F Z E E
N B A T C C K L T 0
B Y J N I X Q I R D
Q G A E S N Y V A V
T T N H C D G J U F
K R J I O T U A Q C
R
X
F
P
U
P
N
D
A
F
R
T
Y
C
Y
I
G
N
K
U
O
R
Z
I
I C L D
V V E G
E R E R
J V E T
0 Q J P S M N A I S
Z J C W A M H G N D
LENS
GRATING
TRANSDUCER
PRISM
TRACKING
QUARTERWAVE
SERVO
DIVERGING
MIRROR
OBJECTIVE
Here is the answer key
to October's puzzle:
S•TJ ADVERTISERS
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ANODE
b. ::::
c. :::::
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d.
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CATHODE
CATHODE
68. What is the main difference between the function of the SCR and that of the
triac?
a. The SCR performs better than the triac.
b. The SCR is a switching device, while the triac is an amplifying device.
c. The SCR can be triggered into conduction in only one direction, while the
triac can be switched on for current in either direction.
d The SCR is made of silicon but the triac is not.
e. Inside every triac package are two little SCR packages.
69. Photodiodes and phototransistors are used:
a. to sense light by permitting current from some power source to pass in rough
proportion to the intensity of light falling on the device.
b. to generate light for transmitting information or providing useful illumination.
c. to block current when light strikes them, and pass current when dark.
d in the "act" section of systems.
e. for the same purposes as standard diodes and transistors.
lnQuizitive Answers (October)
61) b
62) c
63) d
64) e
65) e /
Star*Tech Journal Technical Seminars
-----------------------------
The most recent Star*Tech Journal Seminar & Workshop was held at
Betson Enterprises, Moonachie, NJ on September 12-16.
The students each received a certificate of completion having
successfully finished the 5-day course.
Betson Enterprises sponsored the seminar which covered Basic
Electronics (Electron theory & semiconductors), Video Game
Systems (Power supplies, control panel interfaces, rasterscan and
X-Y monitors), Electronic Pinball Systems (Electronic digital
systems), Troubleshooting Techniques, Test Equipment (Digital
multimeters and logic probes), Proper Soldering Techniques, How to
Read Electronic Schematics and other essential skills.
Future Star*Tech Journal Seminars will include Laser Disc
Operation and Maintenance.
Distributor-sponsored S*TJ Technical Seminars are available to
any distributor interested in assisting their clients to understand
operation and maintenance of videos, pins and lasers.
Star* Tech Journal hosts these seminars at no cost to the
distributor.
If you'd like to sponsor this 5-day course, contact Star* Tech
Journal at 609/662-3432 and ask for our information package. This
package helps you plan your promotion for a successful seminar.
MURPHY'S LAW #509
The most vital dimension on any plan or drawing
stands the greatest chance of being omitted.