Stagecraft II: Lighting & Sound Flashcards
What is electrical generation?
Electrical generation is the process of creating electricity from forms of energy.
What are the natural forms of energy
Water, wind, sun, heat from the earth, biomass from plants
Name some ways energy can be transmitted into electrical energy
Static electricity, electromagnetic induction, electrochemistry, photoelectric effect, thermoelectric effect
Explain static electricity
Static electricity, from the physical separation and transport of charge (examples: triboelectric effect and
lightning)
Explain electromagnetic induction
Electromagnetic induction, where an electrical generator, dynamo or alternator transforms kinetic energy (energy of motion) into electricity.
Explain electrochemistry
Electrochemistry, the direct transformation of chemical energy into electricity, as in a battery, fuel cell or nerve impulse
Explain photoelectric effect
Photoelectric effect, is the transformation of light into electrical energy
Explain thermoelectric effect
Thermoelectric effect, direct conversion of temperature differences to electricity
Electricity is most often generated where by what ?
At power stations by electrochemical generators which can be seen around the world
Explain the distribution method
Power plant generates electricity –> transformer steps up footage of the transmission –> transmission lines carry electricity long distances –> neighborhood transformer steps down voltage –> distribution lines carry electricity to houses –> transformers unpause step down electricity before it enters houses
What is the electrical path
- The power supply
- The circuit
- The device
Explain the three components of basic electricity circuit
- A source of electricity: The different
forms as we discussed in Slide #2 Wind
Water, solar etc. - A load: As simple as a light bulb, an
Electrical motor. - An electrical path: As seen in the line
drawing in the file “Electrical Theory”
pg. 13.
The National Electrical Code (NEC) stipulates that the only electrical cables approved for
temporary stage wiring are….
Types S, SO, ST, and STO
S and SO cables are more commonly used than ST and STO, because
their thick rubber jacket can withstand more physical abuse than the thin, heat-resistant thermoplastic insulation of the ST and STO cable. Type S cable is generally used for stage lighting, because SO costs more and its only advantage is that it is impervious to oil
and gasoline.
What are the suggested ways to keep cables and connectors in good operating condition
- When a cable is not in use, coil it and hang it on the wall of the lighting storage room.
- Check cables and connectors periodically, and replace any items that show signs of cracking, chipping, or other deterioration.
- Always disconnect a plug by pulling on the body of the connector, not the cable.
- Keep the connectors clean. Remove any corrosion, paint, grease, or other as soon as they become evident.
- All elements of a cable should be of the same electrical rating; for example, 12-gauge (AWG) cable (capable of carrying 20 amperes of current) should have only 20-ampere-rated connectors, and so forth.
What is the best type of stage connector
Twist-lock connectors
Pin connectors are probably more widely used than twist-lock connectors. Why?
primarily because they have been in existence for so long.
Pin connectors have what three disadvantages
(1) They can be easily disconnected by accident; (2) the pins of the plug do not always make a good electrical connection with the receptacle; and (3) if the cable is connected to a live power source, it is very easy to be shocked, because the metal conductors in the receptacle are not deeply recessed.
What is used to connect two instruments to the same circuit?
two-fer
What is a two-fer
An electrical Y that has female receptacles at the top of the Y and a male plug at the bottom leg of the Y; used to connect two instruments to the same circuit.
Explain the U-Ground Plug and connector
Also known as the Edison plug “Parallel Blade” in the USA, it is found within the domestic, commercial, and Theatrical environment. It is mainly found on most appliances at home in current carrying capacities of 15A and 20A
What does ‘A’ stand for in electricity
“A” stands for Ampere “The measurement of Current”
Explain the Stage pin plug and connector
This plug is exclusively used in the Theatre. It comes in different amperage rating i.e. 15A, 20A, 50A, and 100A.
Explain the Twist lock Plug and connector
This is another plug that is used in the Theater and in some Commercial/Industrial establishments. They also come in varying amperages
Explain the Round Pin plugs and connectors
Mostly found in England and European regions. In the early Theatres in Trinidad e.g. “Queen’s Hall” and the “Little Carib Theatre”, these plugs and connectors were installed in the rig and were also found on extension cables
Explain the CEE form Plugs and Connector
used in the European regional Theatres, also domestic and industrial. CEE form are rated a bit differently, they come in
13A, 16A, 32A, 63A and higher. These amperages are not common in this part of the world.
Explain the Powercon Plugs and Connectors
A locking-type connector similar to the twist lock concept. They do not come in large amperage capabilities, so are mostly found on consoles both audio
and lighting and associated equipment.
Explain the Camloc Power Connectors
These connectors are mostly used for power distribution applications, e.g. Lighting dimmer systems and Audio amplifier systems and anywhere in the industry where high power is used.
Explain the DMX 3& 5 pin cable and connectors
These cables and connectors are used to connect entire Lighting systems
using the DMX protocol.
Explain the CAT5 Cable
found in most digital environments, in relation to the lighting industry these
cables are used to transmit digital information over lighting networks
What is the atom
the smallest particle of a chemical element that retains the structural properties of that element. The atom is the smallest complete building block in
nature
What are the subatomic particles of an atom
Electrons protons and neutrons
What are the charges of each subatomic particle
the proton has a positive charge, the neutron a neutral charge, and the electron a negative charge
What are the two types of current
Direct an alternating
What is direct currentb
the electron flow is in one direction only. The battery demonstration
discussed in the previous section exemplifies direct current. The current flow is always from the negative terminal of a battery to its positive terminal. All batteries are examples of direct-current sources.
What is alternating-current
the overwhelming majority of electrical power generated by power stations throughout the world is alternating current (AC). The electron flow in AC is the same as in DC with one exception: The current flow periodically changes polarity, which causes the electron flow tochange direction.
What are the electrical circuits
Two primary types of circuits, series and parallel, are used to distribute electricity. A third type, known as a combination circuit, combines the principles of the two.
What is a series circuit
all of the electricity flows through every element of the circuit
What is a parallel circuit
only a portion of the electricity flows through each of the branches of the circuit
Why is sound essential
Communication, alerts and notifications safety, entertainment
What makes good sound in the theatre
CLARITY
BALANCE
INTELLIGIBILITY
AUDIBILITY
FIDELITY
ACOUSTICS
What makes bad sound in the theatre
LACK OF CLARITY - DISTORTION
IMBALANCE - Too Loud or Too Soft
INAUDIBLE
UN-INTELLIGIBLE - Confusion
TECHNICAL DISTURBANCES -
Speaker feedback!
ENVIRONMENTAL DISTURBANCES –
AC Noise, Generator Noise
What is sound
a form of energy produced by an object’s vibration, causing molecules in the medium to travel or vibrate back and forth in the same direction as the wave
What does a sound wave do
Waves transfer energy from one
place to another through a series
of disturbances or vibrations that
carry energy.
Three Things vibrate in Sound:
Source object, molecules in the air, eardrum
What are the properties of sound
Amplitude (loudness), wavelength, frequency (pitch), speed
Explain amplitude
a measure of how loud or soft a sound is
What is dB and what is it
Decibel, a unit measuring the intensity of a sound or the power level of an electrical signal
Explain wavelength
the measure of a wave cycle, how short or long is the wave
Explain frequency
A measurement of how many sound waves pass through per second. Measure in hertz (hz)
Explain the speed of sound
refers to how fast a sound wave is passed from particle to particle through a medium
What is acoustics
a study of how sound behaves in
different environments
Explain reflection, absorption and diffraction
Soft materials like carpets or curtains
can absorb sound, while hard surfaces
like walls or glass reflect sound. Diffraction is the spreading out of waves as they pass through an aperture or around objects.
Explain phase
INTERFERENCE OF SOUND WAVES
* When two or more sound waves from different
sources are present at the same time, they interact
with each other to produce a new wave.
* Wave interaction is called interference.
What are the two types of interference (explain)
IN-PHASE / Constructive interference:
When two sound waves line up, they strengthen each other
and create a wave with a higher intensity.
OUT-OF-PHASE / Destructive interference:
When two sound waves line up, their interaction creates a
wave with a dampened or lower intensity - called Phase
Cancelation
