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February 23, 2003

                             ET NEWS
================================================================
        NEWS AND INFORMATION FOR ENGINEERING TECHNICIANS
----------------------------------------------------------------
Issue No. 87           http://www.etnews.org           2-23-2003
================================================================

Contents
--------
- News
- ET Journal
- NICET Test Dates
- AFAA Class Schedule
- Comments & Acknowledgements

================================================================
NEWS
================================================================

NICET
-----
As you prepare for an examination, be sure to check the list of
codes and standards used to write test questions so that you are
using the correct version. That list can be found here -
http://www.nicet.org/publications/firestandards.pdf. You may
want to bookmark it for future reference because its location on
the NICET web site is not real straightforward (in my opinion):
-> nicet.org
-> Certification
-> Select a Fire Protection Program
-> Fire Alarm Systems
-> Standard Editions Referenced in Fire Protection Exams

----------------------------------------------------------------

I'm off to Honolulu this week.

Have fun!

Mike

================================================================
ET JOURNAL
================================================================

NICET Fire Alarm Systems Level III
35007 BASIC ELECTRONICS
----------------------------------

35007 is a Level III General Core Work element.

General Work Elements are categorized as either Core or Non-Core
Work Elements. All Level III General Core Work Elements
constitute a mandatory requirement for achieving certification at
Levels III and IV.

35007 DESCRIPTION
Understand basic electronic circuits, components, and concepts,
including inductance, capacitance, relays, LED's, transistor
switches, diodes, oscillators, and amplifiers.

35007 REFERENCES:
None given

35007 DESCRIPTION BREAKDOWN:
"Understand basic electronic circuits, components, and concepts,
including inductance, capacitance, relays, LED's, transistor
switches, diodes, oscillators, and amplifiers."

GLOSSARY OF TERMS
-----------------
Class A Amplifier. An amplifier in which the operating point is
chosen so that there is collector current during the entire input
signal cycle (360°).

Class AB Amplifier. An amplifier in which the operating point is
chosen so that there is collector current for more than half but
less than the entire input signal cycle (between 180° and 360°).

Class B Amplifier. An amplifier in which the operating point is
chosen so that there is collector current for almost half of the
input signal cycle (approximately 180°).

Class C Amplifier. An amplifier in which the operating point is
chosen so that there is collector current for considerably less
than half of the input signal (less than 180°).

Common-Base (CB) Amplifier. A transistor amplifier circuit in
which the base is the common or grounded element. The input is
applied to the emitter and the output is taken at the collector.

Common-Collector (CC) Amplifier. A transistor amplifier circuit
in which the collector is the common or grounded element. The
input is applied to the base and the output is taken at the
emitter. Also called an emitter follower.

Common-Emitter (CE) Amplifier. A transistor amplifier circuit in
which the emitter is the common or grounded element. The input is
applied to the base and the output is taken at the collector.

Coupling. The process of transferring a signal from one stage to
the next state.

Direct Coupling. A method of transferring a signal from one point
to another by means of a conductive connection.

Gain. The ratio of the output signal voltage, current, or power
of an amplifier to the input signal voltage, current, or power of
the amplifier.

Impedance Coupling. A method of transferring a signal between
stages in which an inductor is the load component in one stage,
resistors are the input components in the other stage, and a
capacitor provides a path for the signal between the two stages.

Linear Amplifier. An amplifier that operates only on the straight
part of the characteristic transfer curve.

Power Amplifier. An amplifier designed to supply a load that
requires both high current and voltage signals.

Resistance-Capacitance (RC) Coupling. A method of transferring a
signal between stages in which resistors form the output load of
one stage and the input circuit of the other stage. A capacitor
provides a path for the signal between them.

Transformer Coupling. A method of transferring a signal by
applying the output of the source to the primary of a transformer
and taking the input to the load from the secondary.

Voltage Amplifier. An amplifier designed primarily to supply a
large voltage signal to the load.

Distributed intelligence, sometimes called "local mode", is a
feature that may be specified to enable multiplex fire alarm
system transponders to act independently as control panels if the
CPU fails.

When replacing a memory chip, you should ground yourself to the
chassis of the control you are working on.

If the standby power needs of a fire alarm system are calculated
to be 14.3 ampere-hours, a battery rated at 15 ampere-hours may
not be adequate due to its discharge curve. Read the
manufacturer's documentation. Batteries may 50% of their capacity
over their life, which is approximately 4-5.

A bridge rectifier produces full-wave conversion of sine wave AC
power to DC.

If an emergency voice/alarm system speaker, with its 1-watt tap
connected, produces a sound pressure level of 85 dB, then with
its 4-watt tap connected, the sound pressure level will be 91dB.
Doubling the power increase sound pressure level by 3 dB.

The Inverse Square Law states that as a sound wave travels away
from its source, its intensity, or sound pressure level, is
inversely proportional to the square of D, the distance from its
source. Therefore, the intensity of a sound wave when
D = 2 meters is only 1/4 of what it was at 1 meter; at 3 meters,
it’ll be 1/9, and at 4 meters, 1/16. In decibels, 1/4 power is
equal to -6 dB; that’s why the Inverse Square Law is often stated
as:

"Loose 6 dB every time you double the distance." (Anechoic)

Sound waves travel outward from a source, such as a loudspeaker
or a person’s mouth, in all directions. The sound might be
stronger in some directions than others, but it all travels at
the same velocity. Therefore, sound waves tend to be spherical,
or partially spherical, around the source. The area of a sphere
is proportional to the square of its radius (analogous to D); the
energy of the sound wave is distributed over this area. If you
think of sound intensity as force/ area, such as dynes per square
centimeter, you can see how the increasing spherical area causes
intensity to diminish accordingly.

The difference in sound pressure level between distance D1 and a
reference distance D2, is equal in decibels to:
dB = -10 X log (D1/D2)

If an electrician measures line voltage to be 120 VAC at the
branch circuit receptacle, the peak voltage can be determined by
using the formula:
120 VAC / .707 = 170 VAC

In a common-emitter amplifier circuit, the emitter-base junction
is normally forward biased.

To determine the resistance of a particular size of copper wire,
use the formula:

R = p (L / A)

R = Resistance in ohms

p = (Greek letter rho) Resistivity of a material (i.e. copper) in
ohms of resistance for a one-foot length of the material that has
a cross-sectional area of one mil.

L = Length in feet

A = Area in circular mils

Example: What is the resistance represented by 1000 feet of AWG
14 stranded copper wire. Assume the resistivity of copper to be
13.4 ohm-circular mills / foot and NFPA 70 Table 8 indicates
AWG 14 stranded copper wire has a cross-sectional area of 4110
circular mils:

R = 13.4 ohm-cm X 1000 feet
         ------   ---------
         1 foot   4110 cm 

R = 13400 ohm-cm-ft
    ---------------
    4110 ft-cm

R = 3.26 ohm

To determine the effective total capacitance represented by two
50 mfd capacitors connected in parallel, add the individual
capacitances: 50 mfd + 50 mfd = 100 mfd.

If these same two capacitors were connected in series use the
product over the sum:

50 mfd X 50 mfd = 25 mfd
---------------
50 mfd + 50 mfd


THE INFORMATION HEREIN IS PROVIDED AS A GUIDE ONLY AND IS
INTENDED TO ASSIST YOU IN PREPARING FOR AN EXAM. IT IS NOT
INTENDED TO BE INCLUSIVE OF ALL INFORMATION THAT MAY BE ON AN
EXAM BUT RATHER IT IS INTENDED TO BE A SMALL SAMPLE OF THE KIND
OF MATERIAL THAT YOU MAY BE EXPECTED TO KNOW.

================================================================
NICET TEST DATES
================================================================

OREGON
------
OR1 PCC Sylvania, Portland;
Test 4/26/03. Postmark deadline 3/8/03.
Test 7/26/03. Postmark deadline 6/7/03.

OR2 Clackamas Community College, Oregon City;
Test 3/15/03. Postmark deadline 2/1/03.
Test 6/21/03. Postmark deadline 5/3/03.

WASHINGTON
----------
WA1 Bates Technical College, Tacoma;
Test 5/17/03. Postmark deadline 3/29/03.
Test 7/26/03. Postmark deadline 6/7/03.

WA2 Walla Walla Community College;
Test 5/17/03. Postmark deadline 3/29/03.
Test 9/27/03. Postmark deadline 8/9/03.

WA3 Spokane Community College;
Test 5/17/03. Postmark deadline 3/29/03.
Test 8/23/03. Postmark deadline 7/7/03.

These dates are from the NICET web site. For a complete list of
all test centers and test dates, visit:
http://63.70.211.210/cfdocs/nicetschedule.cfm

================================================================
AFAA CLASS SCHEDULE
================================================================

------------------
February 25-27, 2003 Honolulu, HI
Co-sponsored by SFPE Hawaii Chapter 
------------------
Intermediate Fire Alarm Seminar.
http://www.afaa.org/afaa/PDF/IntFA_Honolulu_Feb2003.pdf

------------------
March 11-13, 2003 Dallas, TX - Sponsored by NSCA
------------------
Intermediate Fire Alarm Seminar.
http://www.nsca.org/nscaweb/content/expo2003/attendee/class.asp?
t=4&document=854&a=10&c=2

------------------
March 11-13, 2003 Deerfield Beach, FL (Ft. Lauderdale)
------------------
Intermediate Fire Alarm Seminar.
http://www.afaa.org/afaa/PDF/IntFA_Deerfield_March2003.pdf

------------------
March 17-20, 2003 Oakland, CA - Sponsored by CAFAA
------------------
Fire Alarm System Testing and Inspection Seminar.
http://www.afaa.org/afaa/PDF/ADV_TI_Oakland_Mar2003.pdf
Advanced Fire Alarm Seminar.
http://www.afaa.org/afaa/PDF/ADV_TI_Oakland_Mar2003.pdf

------------------
March 25-26, 2003 Las Vegas, NV - Sponsored by ISC West
------------------
Fire Alarm System Testing and Inspection Seminar.
http://www.iscwest.com/App/homepage.cfm?linkid=7623&moduleid=331
&speakerdetails=speakerdetails&pram=15433&appname=180&date=03/25
/2003

------------------
April 7-9, 2003 New Orleans, LA
Sponsored by LA AFAA
------------------
Advanced Fire Alarm Seminar.
http://www.afaa.org/afaa/PDF/ADV_NewOrleans_April2003.pdf

------------------
April 22-24, 2003 Richmond, VA - Sponsored by VA AFAA
------------------
Advanced Fire Alarm Seminar.
More information will be available soon!

------------------
April 22-24, 2003 Boise, ID
------------------
Intermediate Fire Alarm Seminar.
http://www.afaa.org/afaa/PDF/IntFA_Boise_April2003.pdf

------------------
April 29-30 & May 1, 2003 Seattle, WA
------------------
Intermediate Fire Alarm Seminar.
http://www.afaa.org/afaa/PDF/IntFA_Seattle_April2003.pdf

================================================================
COMMENTS AND ACKNOWLEDGEMENTS
================================================================

ET News is published weekly and if possible, delivered on Sunday

ET News website http://etnews.org by: http://metrodenver.org

----------------------------------------------------------------
The NICET acronym found herein refers to: http://www.nicet.org
NATIONAL INSTITUTE FOR CERTIFICATION IN ENGINEERING TECHNOLOGIES
----------------------------------------------------------------
The AFAA acronym found herein refers to: http://www.afaa.org
AUTOMATIC FIRE ALARM ASSOCIATION "AFAA is celebrating 50 years!"
----------------------------------------------------------------
Some information may be found within this email message that is
reprinted with permission from one or more of the following;
NFPA 70 National Electrical Code(r), NFPA 72 National Fire Alarm
Code(r), and NFPA 101(r) Life Safety Code(r), Copyright(c) NFPA,
Quincy, MA  02269. This reprinted material is not the complete
and official position of the NFPA on the referenced subject,
which is represented only by the standard in its entirety.
================================================================
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This reprinted material is not the complete and official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety.