Function Generator Pitfalls
The Tenma 72-5015 Sweep Function Generator has many features
that are not used in PHYS 101L and PHYS 102L.
User error typically involves these extended features because the user
is unaware of the effects. A detailed
description of the generator is at
http://www.physics.unc.edu/~fredb/techresource/docs/Tenma72-5015.pdf
Getting Started:
- Configure
the function generator front panel according to the following Reference
Configuration. Observe the output
with an oscilloscope and become familiar with each generator feature and
its effects.
Reference Configuration:
CONTROL POSITION
Power ON
Frequency Multiplier 1K
Frequency Dial Center
Duty Cal.
DC Offset Centered
Amplitude Centered
Invert Out
ATT-20dB/-40dB Out
Mode Square Wave
Some past user
problems with function generators:
- Attaching
the signal cable to the counter input rather than the generator output.
- Activating
the sweep function when a single frequency is required.
Some other possible user
problems:
- Output
attenuation function actuated, limiting output signal amplitude.
- CMOS
output selected rather than TTL output, allowing for signal levels outside
of TTL specification.
- External
counter selected when internal generator frequency display is desired.
- Improper
counter gate time selected, reducing frequency resolution from optimum.
- Counter
input attenuator activated, reducing external counter sensitivity.