   About RF Cafe Copyright: 1996 - 2024Webmaster:     BSEE - KB3UON RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived... All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged. My Hobby Website: AirplanesAndRockets.com # Module 1 - Introduction to Matter, Energy, and Direct CurrentNavy Electricity and Electronics Training Series (NEETS)Chapter 3:  Pages 3-121 through 3-126

Module 1 − Introduction to Matter, Energy, and Direct Current

Pages i, 1−1, 1−11, 1−21, 1−31, 1−41, 1−51, 1−61, 2−1, 2−11, 2−21, 3−1, 3−11, 3−21, 3−31, 3−41, 3−51, 3−61, 3−71, 3−81, 3−91, 3−101, 3−111, 3−121, Appendix I, II, III, IV, V, Index

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Equipment PROTECTION from short-circuit current is accomplished by use of fuses and other circuit protection devices.

A Voltage DIVIDER is a series circuit in which desired portions of the source voltage may be tapped off for use in equipment. Both negative and positive voltage can be provided to the loads by the proper selection of the reference point (ground).

3-121 ELECTRICAL Safety PRECautionS must be observed. a fatal shock can occur from 0.1 ampere of current. Voltages as low as 30 volts have been recorded as causing sufficient current to be fatal.

ALL LIVE ELECTRICAL Circuits shall be treated as potential hazards at all times.

ELECTRONIC or ELECTRICAL Equipment discovered to be faulty or unsafe should be reported immediately to proper authority.

ELECTRICAL or ELECTRONIC Equipment should be used and repaired by authorized personnel only.

A CO2 EXTINGUIsHER should be used to extinguish electrical fires.

First AID for ELECTRICAL SHOCK includes the following actions:

.         Remove the victim from the source of the shock.

.         Check the victim to see if the person is breathing.

.         If the victim is not breathing, give artificial ventilation. The preferred method is mouth-to-mouth.

.         CPR may be necessary if the heartbeat has stopped, but do not attempt this unless you have been trained in its use. OBTAIN MEDICAL ASSIsTANCE AS SOON AS POSSIBLE.

3-122

Answers to Questions Q1. Through Q61.

A1.  (a) DS1, the flashlight bulb (b) BAT, the dry cell

A2.  The path for current is incomplete; or, there is no path for current with S1 open.

A3.  a schematic diagram.

A4.  (a) Current increases (b) Current decreases

A5.   (a) Current decreases (b) Current increases A6. A7.  1.25 amperes.

A8.  4 amperes.

A9.  Power.

A10.  By changing the circuit resistance or the voltage of the power source.

A11. A12.  6 amperes.

A13.  a wirewound resistor.

A14.  1 kilowatt.

A15.  8,952 watt hours or 8.952 kWh.

A16.  942 (rounded to 3 places).

A17.

(a).  160 ohms

(b).  480 ohms

3-123

A18.

E1 = 60 volts

E2 = 180 volts

E3 = 240 volts

A19.

E1 = 80 volts

E2 = 240 volts

E3 = 320 volts

A20.  The source voltage would have to be increased to 640 volts.

A21.

(a)  330 ohms

(b)  E1 = 150 volts

E2 = 18 volts

(c)  1.98 kilowatts

(d)  P1 = 900 watts

P2 = 1.08 kilowatts

A22.  The point at which current enters the resistor is assigned a negative polarity and the point at which current leaves the resistor is assigned a positive polarity.

A23.  2 amperes. A24.  120 volts. A25.  50 volts.

A26.   Zero volts.

A27.  a circuit where there is no longer a complete path for current flow.

A28.  An accidental path of low resistance which passes an abnormally high amount of current.

A29.   The internal (source) resistance of the battery will drop some of the voltage.

A30.  When the load resistance equals the source resistance.

A31.   50 percent.

3-124

A32. A33.  60 volts.

A34.  Total current in a series circuit flows through every circuit component but in a parallel circuit total current divides among the available paths.

A35.  Whether the current is entering the junction (+) or leaving the junction (-).

A36. A37. A38. A39.  Equivalent resistor or Req.

A40.  In both cases all the power used in the circuit must come from the source.

A41. A42.  PT  = 60 W, ER2 = 10 V.

A43.   4

A44.   25

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A45.  Because of the 2-volt drop across the internal resistance, only 48 volts is available for the rest of the circuit.

A46.  (a) Total resistance increases, total current decreases (b) Total resistance becomes infinite, total current is equal to zero

A47.  (a) Total resistance decreases, total current increases (b) Total resistance decreases, total current increases

A48.  None.

A49.  The source voltage and load requirements (voltage and current).

A50.   45 mA rule-of-thumb.

A51.   2 k

A52.  495 mA.

A53.  R1  is the bleeder resistor. Bleeder current must be known before any of the remaining divider resistor ohmic values can be computed.

A54.  (a) By adding the bleeder current (IR1) and the current through load 1(b) By subtracting the voltage of load 1 from the voltage of load 2.

A55.  1.35 watts.

A56.  The series-parallel network drops the remaining source voltage and is used to take the place of a single resistor (75 ohms) when the required ohmic value is not available in a single resistor.

A57.  R3    = 2 watts; R5  = 6 watts.

A58.  The ground (reference point) is placed in the proper point in the voltage divider so that positive and negative voltages are supplied.

A59.  NEVER! All energized electric circuits should be considered potentially dangerous.

A60.   You should immediately report this condition to a qualified technician.

A61.  Only trained, qualified personnel.

3-126

 NEETS Modules - Matter, Energy, and Direct Current - Alternating Current and Transformers - Circuit Protection, Control, and Measurement - Electrical Conductors, Wiring Techniques, and Schematic Reading - Generators and Motors - Electronic Emission, Tubes, and Power Supplies - Solid-State Devices and Power Supplies - Amplifiers - Wave-Generation and Wave-Shaping Circuits - Wave Propagation, Transmission Lines, and Antennas - Microwave Principles - Modulation Principles - Introduction to Number Systems and Logic Circuits - - Introduction to Microelectronics - Principles of Synchros, Servos, and Gyros - Introduction to Test Equipment - Radio-Frequency Communications Principles - Radar Principles - The Technician's Handbook, Master Glossary - Test Methods and Practices - Introduction to Digital Computers - Magnetic Recording - Introduction to Fiber Optics Note: Navy Electricity and Electronics Training Series (NEETS) content is U.S. Navy property in the public domain.   Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created. These Are Available for Free