Elenco 3 1/2 Digit Cap. / Trans. Kit - Manual (Page 18)

PARTS LIST - SECTION D
RESISTORS
Qty. Symbol Description Color Code Part #
r 1 R54 10k
Ω
5% brown-black-orange-gold 151000
r
1 R52 100k
Ω
5% brown-black-yellow-gold 161000
r 2 R55, R57 330k
Ω
5% orange-orange-yellow-gold 163300
r 4 R51,53,56,58 1M
Ω
5% brown-black-green-gold 171000
r
1 PTC 1.5k
Ω
Thermister 190416
CAPACITORS
Qty. Symbol Value Description Part #
r 2 C16, C17 .001
μ
F (102) Discap 231036
MISCELLANEOUS
Qty. Symbol Value Description Part #
r 1 Buz Buzzer (20mm dia.) 595220
SECTION D
Resistance & Buzzer Circuit
-17-
Top Legend Side
R39 - 6.8k
Ω
5% 1/4W Res.
(blue-gray-red-gold)
(see Figure I)
C11 - 10
μ
F Lytic Capacitor
(see Figure B)
VR2 - 200
Ω
Pot (201)
R34 - 100k
Ω
5% 1/4W Res.
(brown-black-yellow-brown)
(see Figure I)
IC Socket 14-pin
IC2 - LM324 Op-Amp IC
(see Figure M)
Figure M
Insert the IC socket into the PC
board with the notch in the same
direction marked on the top legend.
Solder the IC socket into place.
Insert the IC into the socket with the
notch in the same direction as the
notch on the socket.
Socket
IC
PC Board
Notch
ASSEMBLE THE FOLLOWING COMPONENTS TO THE PC BOARD
Assembled View
r Attach the LCD to the PC board using the two 2.5 x 8mm screws. Use the top-mounting hole and lightly
tighten the screws. The screws will be removed to assemble the next section.
-18-
AC Voltage Test
Caution do not handle the PC board during the
Voltage or Current test. If you do an AC source, set
VR2 to its middle position.
1. Placing the top label over the knob will assist in
obtaining the correct knob position when doing
tests.
2. Connect the 9V battery to the battery snap.
3. Connect the test leads (red lead to V
Ω
and black
to COM). Turn the meter on by pressing the power
switch.
4. Obtain an AC voltage and set the meter to the
appropriate range.
5. Using another meter of known accuracy, measure
the AC voltage. You will calibrate the kit meter by
measuring the same voltage source and
adjusting VR2 until the kit meter reads the same
as the accurate meter. When the two meters
agree, the AC voltage circuit is calibrated. Turn
the meter off and continue to the Current Test.
If the tests are not working, check components R34
– R39, VR2, C7-C11, and IC2.
AC Current Test
1. Turn the range selector knob to the 200mA AC
current position.
2. Connect the test leads (red lead to
μ
A/mA and
black to COM) to the meter.
3. Connect the kit meter and another meter of
known accuracy in series. Set the meters to the
200mA position. Construct a circuit for an AC
current (for example 12VAC and a 100
Ω
resistor
for 120mA) and connect the meters to the circuit.
4. Turn the meters on and both should have close to
the same readings. Check the other current scale
by changing the voltage or resistance values. The
20A scale requires a circuit of 1-20 amps. For the
20A shunt wire adjustment, refer to page 32.
If the kit meter does not agree, check the parts just
added. Do not readjust VR2 for this will change the
AC voltage read. If the tests are not working, check
for cold solder joints and part values. Turn the meter
off and remove the battery and test leads.
DO NOT
PROCEED TO SECTION D WITHOUT YOUR
INSTRUCTOR’S APPROVAL.
Remove the two display mounting screws and
display by unscrewing the two mounting screws.
ASSEMBLE THE FOLLOWING COMPONENTS TO THE PC BOARD
R58 - 1M
Ω
5% 1/4W Res.
R51 - 1M
Ω
5% 1/4W Res.
(brown-black-green-gold)
(see Figure I)
R55 - 330k
Ω
5% 1/4W Res.
(orange-orange-yellow-gold)
(see Figure I)
R52 - 100k
Ω
5% 1/4W Res.
(brown-black-yellow-gold)
(see Figure I)
R54 - 10k
Ω
5% 1/4W Res.
(brown-black-orange-gold)
(see Figure I)
Top Legend Side
Bottom Legend Side
BUZ - Buzzer
(see Figure N)
R56 - 1M
Ω
5% 1/4W Res.
(brown-black-green-gold)
(see Figure I)
C17 - .001
μ
F (102) Discap
C16 - .001
μ
F (102) Discap
R57 - 330k
Ω
5% 1/4W Res.
(orange-orange-yellow-gold)
(see Figure I)
R53 - 1M
Ω
5% 1/4W Res.
(brown-black-green-gold)
(see Figure I)
PTC - 1.5k
Ω
Thermister
Figure N
Solder the edge of the buzzer to the points shown
on the PC board. Then solder a discarded resistor
lead to the middle of the buzzer and to the point
shown on the PC board. Buzzer
Solder
Points
PC Board
Discarded
Resistor
Lead
Solder
Points
Solder
Solder
Assembled View