Fluke 77/BN - Touch Hold Erp

TOUCH HOLD
TOUCH HOLD
In Touch Hold, the meter "captures" a
reading when the test leads touch a
circuitor when the range push button is
pressed. This allows you to lift the test
leads before reading the display.
WARNING
DO NOT USE TOUCH HOLD TO DE-
TERMINE IF A CIRCUIT WITH HIGH
VOLTAGE IS DEAD.
The meter will capture a reading if the
input is constant for 1/2 second and if
at least one segment of the analog
display differs from the previous read-
ing. However, the meter will not cap-
ture a reading if the input is overrange
or near zero volts or amps. In some
functions, therefore, the meter may not
display a reading on power-up. Press-
ing the range push button will force a
reading. The Touch Hold is always in
autorange, so the meter will up-range
if necessary.
Open test leads in noisy environments
may pick up stray signals. It is there-
fore possible for an unwanted update
(signaled by an extra beep) to occur.
An unwanted update is most likely to
occur in one of the following situations:
1. When test leads are exposed to
large rf or other ac fields.
2. When one test lead is connected to
a voltage source and the other test
lead body is held by the operator.
3. When the high side (red) metal probe
tip is touched by the operator.
4. When used in high voltage environ-
ments where dielectric energy, stored
in materials and on operator's hands,
is released slowly into open leads just
after making a Touch Hold measure-
ment above a few hundred volts.