Star Tech Journal

December 1996
STAR*TEcH
Overview of the Reed Switch Ball Sensor:
Consists of a Diode (1N4004) and a HSR-042 Reed Switch. The
Cable Wiring Harness has the Green Wire going to the switch and
the White Wire going to the Anode side of the Diode. The Contact
Rating is 100 Volts AC/DC, 0.2 Amps AC/DC, 4 Watts (Resistance
Load) & 2 Watts (Inductive Load). The Temperature Operation
Range: 0-150° F.
Reed Switch Assy. Plastic Case
r----1
GREEN
WIRE
Journal
Magnet
Side
0
'
(TOP VIEvV)
WHITE
WIRE
L - - - - I 1N4004
I
I I
I
(SIDE VIEW)
Sealed Glass Tube
REED SWITCH BALL SENSOR THEORY OF OPERATION
Here's how it works:
• Two magnets of equal strength creating a bal-
anced magnetic field.
Glass Tube
with contacts
f
The Reed Switch is positioned in the balanced field •
[
t
..
As a pinball passes in close prox-
imity to the bottom magnet, it
disturbs the balanced field. The
lower magnet is strengthened by
the presence of the pinball, thus
operating the Reed Switch con-
tacts.
The Reed Switch contacts are
hermetically sealed in a glass
tube, filled with inert gas to pro-
vide long life with stable electri-
cal and operating characteristics .
The magnets, the glass tube (with
contacts), the Green & White
Wires & Diode are sealed in the
Plastic Reed Switch Housing in
soft epoxy.