Heathkit IM-16 - Output Circuit; Power Supply

-
lryl
Resistance
is measured by
clipping
the
common
test
lead
and the test
probetiptothe
two ends of
the
unlcrown resistance,
The
OHMS
range
switch
is
then turned to a
position
where a
clear
read-
ing
is
given
on
the meter.
Multiply
the reading
as indicated
by
the
switch
position.
The
voltage
the
ohmmeter
placesacrossthetest
component
is in the
order
of
.?
volts or less.
This
low
voltage
permits
resistance
m.easure-
ments in solid state
circuits,
as it is
not
suf-
ficient to
cause
transistors to
conduct
and
present
a
shunt
to
the
circuit"
However, diodes
or
transistors
cannot be checked
for
junction
resistance
since
the
applied
voltage is so low
that the device willnot
conduct
in either
direction
and
a
good
device will appear
to
be
open"
NOTE: Although
a battery
is used
to measure
resistance,
the indication
is
obtainedthroughthe
electronic
meter circuit;
therefore
the instru-
ment must be
turned on.
Some ohmmeter
bat-
tery current
is
drawn whenever
the instrument
is
turned
on
and the
FUNCTION switch
is in
the
OHMS
position. To
save battery
life
when
you
are
not
using
the
ohmmeter,
NEVER LEAVE
THE
FUNCTION
SWITCH
IN
THE
OHMS
POSITION.
DC Voltoge Reodings
For
DC
voltage measurements,
theprobeswitch
must
be in the
DC
position.
The FUNCTION
switch
can
be
at DC+
or
DC-,
depending
on
whether
a
positive
or
a negative
voltage isto
be
applied
to
the
probe
tip" This
is
convenientwhen
measuring
voltages at
several
points
in a
cir-
cuit,
some
positive
and
some negative
with
respect
to a
common
point.
The
common test
lead may
remain
connected
to the
common
volt-
age
point,
and the FUNCTION
switch changed to
DC+
or
DC-
for the appropriate
polarity.
DC
voltages are
read
on
either
of
the
two
black
meter
scales,
whieh are marked
0-15
and
0-50.
The
markings
on
the VOLTS range
switch
refer
to the voltage that will
give
a
full-scale reading
on
either
of
the black scales
when measuring
DC
voltage.
The
lowest
VOLTS
range switch
position
is
marked
.5.
This
means
that
.5
volt applied
to
the
probe
tip will
cause
a full-scale
deflection
of
the meter
pointer,
or
indicate
50onthe scale.
To read voltage in
the
.5
volt range,
read
the
50
scale
and move
the decimal two
places
to
the
left.
For
example,
a
reading of
20wouldindicate
"2
volt
.
To read
voltage on
the 1.5 volt range, read
the
15
scale
and
move the decimal one
place
to
the
left.
For example,
a meter reading
of
B would
indicate an
actual measurement
of
.8
volt.
For
the
5
volt range,
read
the
50
scale
and move
the
decimal
one
place
to the left.
For
example,
a
meter
reading of
40
would indicate
a measure-
ment
of
4 volts.
On
the
15 V range,
read
the
15
scale
directly,
On the
50
V
range,
read
the
50
scale
direetly"
On
the 150
V range, read
the 15 scale
and
move
the
decimal
one
place
to the right"
For
example,
a
meter
reading of
1
3
would
indicate
1
30
volts. On
the
500
V
range,
read
the
50
scale
and
move
the
decimal one
place
to the right.
For
example,
a
meter
reading of
40 would indicate
400 volts.
When
using
the
1500
V range, use
the 15 scale
and
move the decimal
two
places
to
the
right.
For
example, a meter reading of
12 would
indi-
cate 1200 volts.
AC VOLTAGE
READINGS
The FIJNCTION
switch
and
the
probe
switch
must
be
in the
AC positionforACvoltage meas-
urements.
With
the VOLTS range switch
in one
of
the
four clockwise
positions
(50,
150,
500, or
1500),
AC
voltages
are read
on
one of
the
two
black
scales, inthe same
manner
as
DC
voltages.
For the
four lower
AC
voltage
ranges
(.5,
1.5,
5,
or 15), separate
scales,
printed
in red,
are
provided.
When the
VOLTS range
switch
is in the
.5
posi-
tion,
AC
voltage
is
read
directly
on
the
bottom
red scale
of
the meter. Note that this
scale ex-
tends to
.65
and the
.5
reading is approximately
2/3
of.
full
scale" Thus, the
.5
volt
AC
range is
actually
extended to
.65
volts.
In the
1.5
position
of
the
VOLTS range
switch,
AC
voltage
is read
directly on
the
second
red
scale
from
the
bottom.
This
scale
extends
the
1.5 volt
range
to
1.8 volts.
Read
the third
and
fourth
red
scales
(5
and 15)
directly when
the
VOLTS rangeswitchisinthe
5
and 15
positions
respectively.
The
black 50
scale
is read
directly for
the
50
volt
AC range, or
multiplied
by 10
for
the
500
volt
AC range.
The
black 15
scale
is used
for
the
150 and 1500
positions
of
the VOLTS range
switch.
For the 150
volt
range,
multiply
the
reading
by
ten"
For
the
1500 volt
range,
multiply
the reading
by
100.