3B Scientific Photo Gate User Manual

3B SCIENTIFIC® PHYSICS

Light barrier U11365

Instruction sheet

01/10 Hh/570012

1. Safety instructions

• When using the equipment in conjunction with

a laser source, strictly observe the stipulated
safety regulations.

• Never look directly into the laser beam.

2. Scope of delivery

1 Light barrier
1 Stand rod, length: 120 mm
1 8-pin mini DIN connection cable, length: 1 m
1 Knurled screw M6x1

3. Description

The light barrier can be used in two operating
modes.

1. Internal light barrier mode: light barrier with an
infrared light source and an infra-red detector with
a very short signal delay for measuring time inter­vals with moving bodies, e.g. during free fall, in air

track experiments and for pendulum oscillations,
as well as for counting pulses.

2. Laser light barrier mode: laser diode detector
built in at the side for setting up a wide-range
barrier along with a laser pointer, e.g. during sport­ing events.

The light barrier is equipped with a built-in LED
function display: beam broken = 1 (TTL high).
When disabled or when the beam is interrupted,
the LED function display comes on.

The narrow barrier arm in front of the infra-red
source includes a sliding mechanical shutter that is
used for disabling internal light-barrier mode and
activating laser light -barrier mode.

4. Technical data

Separation of prongs: 82 mm
Rise time: 60 ns
Spatial resolution: < 1 mm
Time resolution: 10 µs

1

5. Operation

• Screw onto the stand rod using the arm at-

tached to the thinner of the two prongs of the
barrier and the M6 nut provided for this pur­pose.

• Insert the mini DIN cable into the mini DIN

connector on the broader prong of the barrier
and connect it to the 3B NETlog

TM

interface

U11300 or to digital counter U210051.

• Activate internal light barrier mode by opening

the mechanical shutter. Subsequently, mount
and focus the device for the intended applica­tion.

• Activate laser light barrier mode by closing the

mechanical shutter and (roughly) focus the la­ser light source onto the opening at the side of
the light barrier. To achieve this, mirrors may
be used to deflect the laser beam. Make fine
adjustments to the light barrier.

6. Applications

Determining the position, velocity and acceleration
of moving bodies

Determining the acceleration due to gravity g in
free fall experiments

Measuring periods of oscillating bodies

7. Sample experiment

Determining acceleration due to gravity g using
picket fence U11366

Required apparatus:

TM

1 3B NETlog

U11300
1 Light barrier U11365
1 Picket fence U11366
1 Stand base U13270
1 Steel rod, length: 750 mm U15003
1 Universal clamp U13255
(1 Foam rubber sheet, approx. 20 x 20 cm)

• Use the stand apparatus to fix the light barrier

at a suitable height above ground level or at
the edge of a table. If necessary, place a cush­ioning surface (e.g. foam rubber sheet) along
the point of impact.

• Select the digital input of the 3B NETlog

face and load the free-fall experiment (tem­plate) from the 3B NETlab

TM

software. All the

TM

inter-

necessary settings required for evaluation are
provided by this software.

• Conduct the experiment and analyse your

results.

Fig. 1: Measuring free fall

Fig. 2: Distance against time

Fig. 3: Fall velocity against time

3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com

Subject to technical amendments

© Copyright 2010 3B Scientific GmbH