Interceptor Link, Solenoid 2, S2 Operation - Polaroid Land SX-70 User Manual

mechanical device identified as the interceptor
connected to the lens focusing mecchanism
(Figure 1-13 A). the interceptor is moved as
the lens is focused regardless of whether
ambient-light or flash pictures are being taken.
When flash bar is in place (S2 closed) and the
gear train opens switchs S5 (Fighure 1-14),
solenoid #2 is energized and pulls the interceptor
into position to phycally restrict the shutter blade
travel (Figure 1-13 B). Since the interceptor is
controlled by the focusing mechanism, the
shutter opening is related to camera-to-subject
distance thus compensating for the flashbulb-to-
subject distance to give proper flash exposure.
As a solenoid #1 de-energizes switch S4 moves
from the CB position to the CA position. This
switch conects VCC to the FFA.
Figure 1-13 A Interceptor link, Solenoid 2, S2 operation - Solenoid de-energized
When the flash delay period reaches completion,
the circuitry removes the holding current from
solenoid #2. Since the solenoid is an electro-
mechanical device, removing power from it
causes a collapsing magnetic field which induces
a fly back voltage. This voltage pulse is fed to
the flash circuitry which then applies the firing
voltage across the flash lamp.