Notes taken from Michael Gillette’s

Designing With Light

Company Switch A disconnect box to

which portable dimmers may be connected

Normally 240 VAC Located in wings

Every theatrical lighting system is made up of three components Dimmers Dimmer Control Electrical Distribution

Two kinds of Dimmers Mechanical Electronic

Involved direct physical movement of mechanical components, not frequently used in theatre anymore

Resistance Dimmer – Archaic dimmer using a variable-capacity resistor

Lights off - resistance increased energy converted to heat and does not reach the lamp

Lights on - resistance decreased and current reaches the lamps

Difficult to use, requires a lot of space,

Saltwater Dimmer Oldest type of dimmer Involved dipping metal plates

attached to one leg of a circuit into salt water with another set of plates already immersed in the water.

Current dependent on depth of metal plates being dipped.

Use a low-voltage current to regulate the high-voltage current

Autotransformer Dimmer Rarely controls stage lights, but sometimes

house lights Control switch in booth regulates a mechanical

linkage that controls the dimmer and enables it to raise and lower the lights

Motor runs a single speed so fades cannot be controlled

Autotransformer Dimmer

Silicon Controlled Rectifier Dimmer (SCR) Operates on a gating

principle On for 1 second – full

intensity On for ½ second, Off for ½

second – 50% intensity On for ¼ second, Off for ¾

second – 25% intensity Solid state power

transistor No moving parts, reliable

Silicon Controlled Rectifier Dimmer (SCR)

Digital Control Systems for Electronic Dimmers The new “Standard”

Digital Control Systems for Electronic Dimmers Analog

Requires a constant signal Every dimmer in the system must be connected

to the light board by its own control line Line –The wires in low-voltage control systems

Digital Control Systems for Electronic Dimmers Digital

Discrete (separate and complete )steps binary code, on, off, 0, 1 Multiplexing – can send multiple messages at the

same time

Analog Digital

Group Master Individual dimmers

controlled by a submaster, which is controlled by a grand master

Preset Two-scene Preset,

Three-scene Preset Controls for each

dimmer are repeated for two or three scenes

Dimmers can be set up for each scene and using a fader can be shifted from scene one to scene two

Combination Combines preset

and group master Provides more

options and flexibility

Computer Memory Most flexibility Hard Drive – Device

for storing and retrieving data

Back-up disk Volatility –

Nonpermanence

Computer Memory Channel Control – An electronic patching

system in which one or more dimmers can be assigned to a control channel which in turn controls the intensity level of those dimmers

Group – grouping of two or more dimmers/channels under one controller

Computer Memory Timing capabilities

Fade-in – gradual increase in intensity Fade-out – gradual decrease in intensity Split time fade – Fade up and out are at

different rates Delay - Refers to the time interval that the

second part of a split time fade follows the first