Movies for TV - Early Television Foundation

FILM TRANSMISSION EQUIPMENT 119
with the camera scanning. To the left can be seen the driving
motor; the knurled knob on the left end of the motor shaft is to
turn the mechanism by hand after threading the film to check its
correctness.
The 1000-watt projection lamp is housed in the narrow section
between the motor and the projector mechanism. It burns con-
it cool.
tinuously and a separate motor-driven blower serves to keep
A condenser and reflector system focusses the light onto the film in
the picture gate. The white lines indicating the film path also used
by RCA can be seen in the picture.
Immediately below the shiny black lens barrel can be seen the
exciter lamp-housing which contains the lamp that shines through
the sound track and with the aid of the photoelectric cell converts
light to sound. In the RCA projector, the lamp does not shine
directly through the film and lens system onto the cell but is re-
flected by a mirror behind the sound drum (the white disc just to
the left of the lamp-housing) onto the photocell.
Shutter
Projection
Reflector / Lam P
Jf Condenser
/^\ lon \
Pull-down Claw
Sou
Optical
Mirror
Feed Sprocket
Projection Lens
Pressure Roller
~V --.^ /Photo Cell
Film Gate
Take-up Sprocket
pper Reel
Iconoscope
Mosaic
Fig. 4-17. Diagram of film path and mechanism of the RCA
16 mm projector.