Graymark 803 - RECTIFIER CIRCUIT MEASUREMENT; Diode Lead Identification; Percent-of-Ripple Test (No Filter)

DIODE
COLOR
BAND
FIG. L
----e.
The resistance
reading
recorded
in step
b
should be
very
low and the
resistance
re-
corded
in
step
cl should be
extremely
high.
Are they?
You can
see
{rom
this test, that
a diode
provides a
path
of
very
Iow resistance
for current
in one direc-
tion and blocks
nearly all
current
in the
other dircction.
2.
Percent-of-Ripple Test
-
No
Filter
For this test
you
will
need a
VTVM
(vacuum-tube
voltmeter
or
TVM
(transistorized
voltmeter)
. The
purpose
of this test
is
to determine
the
percent-of-
Ripple of the
pulsating DC
from the
fuil-wave
rectifier.
-a.
Adjust the
VTVM
to
a range that
wili meas-
ure 50 volts
DC. Connect the
NECATIVE
(-)
test
probe
to bus
r'vire
C,
and the
POSITIVE
(-)
DC
probe
to bus
r,r,ire A.
(Refer
to
Fig.
K).
-tr.
PIug in
the
Iine
cord.
Read and
recorcl this
voitage measurement:
-.lt
should
be
about
20 ve,tlts
DC. This is
the
"E3ys12gs
voltage".
c. UNPLUC
THE LINE
CORD.
Then, change the
meter to a
range that will
measure
15 volts
AC, and substitute
the
AC
test
probe for the
DC
probe connected to bus
wire A.
d.
Plug
in
the
line
cord.
Read and
record this
voltage
measurement:
.
lt should
be about'l
0 volts
AC. This
is
the
"E1mq
of
Ripple
Voltage".
e. UNPLUC
THE LINE CORD.
Remove the
test
probes
from the breadboard.
f . In the space
provided
belor,v,
rvrite the equa-
tion fo
r
calcu
lati
n g percent-of-Ri
pple.
(ilefer
to
Full-wave
Rectifier Discussion)
(1)
%-of-nipple
:
x
-100
g.
In
the space
provided
belorv,
calculate the
percent-of-Ripple
by substituting the
proper
voitages for the
letter
symbols
used
in
the
equation.
The E165
of
Ripple voltage is the
AC measurement
obtained
in
step d
above,
and the
Eaverage
','oltage
is
the
DC
measure-
ment
that
was
obtained
in
step b.
(2)
%
Ripple
(3)
%
Ripple
(4)
%
Ripple
-
The
ok-ol-Ripple
sltould
be about 50oio
-
3.
Have instructor initial
your
Progress Cuide.
x
100
x 100
FIG.
M
p>onava,ranx
MODEL 8
\
BREADBOARD
FIG.
K
11