Elenco Electronics FG-500K User guide

FUNCTION GENERATOR KIT
MODEL FG-500K
Assembly and Instruction Manual
Elenco®Electronics, Inc.
Copyright © 2005 byElenco®Electronics,Inc. All rights reserved. Revised 2005 REV-B 753069
No partof this book shall be reproduced byanymeans; electronic,photocopying, or otherwise without written permission from the publisher.

PARTS LIST
If you are a student, and any parts are missing or damaged, please see instructor or bookstore.
If you purchased this kit from a distributor, catalog, etc., please contact Elenco®Electronics (address/phone/e-
mail is at the back of this manual) for additional assistance, if needed. DO NOT contact your place of purchase
as they will not be able to help you.
RESISTORS
Qty. Symbol Description Color Code Part #
1 R6 200W5% ¼W red-black-brown-gold 132000
1 R1 620W5% ¼W blue-red-brown-gold 136200
1 R5 3.9kW5% ¼W orange-white-red-gold 143900
1 R7 8.2kW5% ¼W gray-red-red-gold 148200
1 R8 10kW5% ¼W brown-black-orange-gold 151000
1 R4 22kW5% ¼W red-red-orange-gold 152200
1 R9 100kW5% ¼W brown-black-yellow-gold 161000
1 R2 10kWPotentiometer 192531
1 R3 100kWPotentiometer 192612
CAPACITORS
Qty. Symbol Value Description Part #
1 C6 820pF (821) 10% Discap 228210
1 C5 .01mF(103) 10% Mylar 241017
1 C4 .1mF(104) 10% Mylar 251017
1C3 1mF50V Electrolytic (Lytic) 261047
3 C2, C7, C8 10mF16V Electrolytic (Lytic) 271015
1 C1 100mF16V Electrolytic (Lytic) 281044
1C9 1,000mF16V Electrolytic (Lytic) 291044
SEMICONDUCTORS
Qty. Symbol Value Description Part #
1 U1 XR-2206 Integrated Circuit 332206
MISCELLANEOUS
-1-
Resistors Capacitors
PARTS IDENTIFICATION
Electrolytic
Integrated Circuit
Switches
Socket
Mylar
Binding Post
Qty. Description Part #
1 PC Board 511003
2 DPDT Switch PC Mount 541009
1 Switch Rotary 2p6pos 542207
1BatterySnap 590098
1 Top Panel 614111
3Knob 622009
1 Jack Ear Phone with Nut 622130
1 Case 623003LP
2Spacer 5/8” 624432
1 Binding Post Black 625031
3 Nut Binding Post 625031HN
3Lockwasher Binding Post 625031LW
Qty. Description Part #
2 Binding Post Yellow 625034
4 Screw 4-40 x ¼” Phillips 641433
3 Hex Nut 7mm 644101
1HexSwitch Nut 9mm 644102
2 Flat Washer 8mm x 14mm 645101
1Flat Washer 9mm 645103
1 16-pin IC Socket 664016
1 Handle 666600
2” Weather Strip 790007
1.5’ Black Wire 22ga. 814120
1 Solder 9ST4
ScrewBatterySnap
Earphone
Jack
PC Mount
Potentiometer
Rotary DPDT
Spacer
Discap
Knob

-2-
INTRODUCTION
Assembly of your FG-500 Function Generator will prove to be an exciting project and give much satisfication and
personal achievement. The FG-500 contains a complete function generator capable of producing sine, square
and triangle wave forms.The frequency of this generator can be contiuously varied from 1Hz to 1MHz in 6 steps.
Afine frequency control makes selection of any frequency in between easy. The amplitude of the wave forms
are adjustable from 0 to 3Vpp. This complete function generator system is suitable for experimentation and
applications bythe student. The entire function generator is comprised of a single XR-2206 monolithic IC and a
limited number of passive circuit components.
SPECIFICATIONS
OUTPUT:
•Waveforms: Sine, Triangle, Square
•Impedance: 600W+ 10%.
•Frequency: 1Hz - 1MHz in 6 decade steps with variable ranges.
SINE WAVE:
•Amplitude: 0 - 3Vpp at 9VDC input.
•Distortion: Less than 1% (at 1kHz).
•Flatness: +0.05dB 1Hz - 100kHz.
SQUARE WAVE:
•Amplitude: 8V (no load) at 9VDC input.
•Rise Time: Less than 50ns (at 1kHz).
•Fall Time: Less than 30ns (at 1kHz).
•Symmetry: Less than 5% (at 1kHz).
TRIANGLE WAVE:
•Amplitude: 0 - 3Vpp at 9VDC input.
•Linearity: Less than 1% (up to 100kHz).
POWER REQUIREMENTS:
•Standard 9V Battery or 9V to 18VDC at input.
OPERATING TEMPERATURE:
• 0OCTO 50OC.
IDENTIFYING CAPACITOR VALUES
Capacitors will be identified by their capacitance value in pF (picofarads), nF (nanofarads) or mF(microfarads).
Most capacitors will have their actual value printed on them. Some capacitors may have their value printed in the
following manner.
Second Digit
First Digit
Multiplier
Tolerance
The above value is 10 x 1,000 = 10,000pF or .01mF
The letter K indicates a tolerance of +10%
The letter J indicates a tolerance of +5%
FortheNo.01234589
Multiply By 1 10 100 1k 10k 100k .01 0.1
Multiplier
Note: The letter “R” maybe used at times to
signify a decimal point; as in 3R3 = 3.3
IDENTIFYING RESISTOR VALUES
Use the following information as a guide in properly identifying the value of resistors.
BAND 1
1st Digit
Color Digit
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9
BAND 2
2nd Digit
Color Digit
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9
Multiplier
Color Multiplier
Black 1
Brown 10
Red 100
Orange 1,000
Yellow 10,000
Green 100,000
Blue 1,000,000
Silver 0.01
Gold 0.1
Resistance
Tolerance
Color Tolerance
Silver +10%
Gold +5%
Brown +1%
Red +2%
Orange +3%
Green +.5%
Blue +.25%
Violet +.1%
Bands
1 2 Multiplier
Tolerance

-3-
Introduction
The most important factor in assembling your FG-500K Function Generator Kit is good soldering techniques.
Using the proper soldering iron is of prime importance. A small pencil type soldering iron of 25 - 40 watts is
recommended. The tip of the iron must be kept clean at all times and well tinned.
Safety Procedures
• Wear eye protection when soldering.
•
Locate soldering iron in an area where you do not have to go around it or reach over it.
•Do not hold solder in your mouth. Solder contains lead and is a toxic substance. Wash your hands
thoroughly after handling solder.
• Be sure that there is adequate ventilation present.
Assemble Components
In all of the following assembly steps, the components must be installed on the top side of the PC board unless
otherwise indicated. The top legend shows where each component goes. The leads pass through the
corresponding holes in the board and are soldered on the foil side.
Use only rosin core solder of 63/37 alloy.
DO NOT USE ACID CORE SOLDER!
CONSTRUCTION
Solder Soldering Iron
Foil
Solder
Soldering Iron
Foil
Component Lead
Soldering Iron
Circuit Board
Foil
Rosin
Soldering iron positioned
incorrectly.
Solder
Gap
Component Lead
Solder
Soldering Iron
Drag
Foil
1. Solder all components from
the copper foil side only.
Push the soldering iron tip
against both the lead and
the circuit board foil.
2. Apply a small amount of
solder to the iron tip. This
allows the heat to leave the
iron and onto the foil.
Immediately apply solder to
the opposite side of the
connection, away from the
iron. Allow the heated
component and the circuit
foil to melt the solder.
1. Insufficient heat -the
solder will not flowonto the
lead as shown.
3. Allowthe solder to flow
around the connection.
Then, remove the solder
and the iron and let the
connection cool. The
solder should have flowed
smoothly and not lump
around the wire lead.
4. Here is what a good solder
connection looks like.
2. Insufficient solder -let the
solder flow over the
connection until it is
covered. Use just enough
solder to cover the
connection.
3. Excessive solder -could
make connections that you
did not intend to between
adjacent foil areas or
terminals.
4. Solder bridges -occur
when solder runs between
circuit paths and creates a
short circuit. This is usually
caused by using too much
solder. To correct this,
simply drag your soldering
iron across the solder
bridge as shown.
What Good Soldering Looks Like
Agood solder connection should be bright, shiny,
smooth, and uniformly flowed over all surfaces.
Types of Poor Soldering Connections

Figure B
Bend the capacitor over before
soldering.
-4-
ASSEMBLE COMPONENTS TO THE PC BOARD
Care must be given to identifying the proper components and in good soldering habits. Refer to the soldering
tips section in this manual before you begin installing the components. Place a check mark in the box after
each step is complete.
Figure A
Electrolytic capacitors
have polarity. Be sure
to mount them with the
negative (--) lead
(marked on side) in the
correct hole.
Mount the electrolytics horizontal to the
PC board. Bend the leads at right
angles and then insert the leads into the
PC board.
Figure D
Insert the IC socket into the PC board
with the notch in the direction shown
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.
Notch
C1 - 100mF16V Electrolytic
(see Figure A)
C2 - 10mF16V Electrolytic
(see Figure A)
C3 - 1mF50V Electrolytic
(see Figure A)
C4 - .1mF10% Mylar (104)
(see Figure B)
C6 - 820pF 10% Discap (821)
C5 - .01mF10% Mylar (103)
(see Figure B)
J4 - 3” Black Wire 22ga.
J8 - 3” BlackWire 22ga.
J7 - 3” BlackWire 22ga.
(see Figure C)
C9 - 1000mF16V Electrolytic
(see Figure A)
S3 - Slide Switch DPDT
R7 - 8.2kW5% ¼W Resistor
(gray-red-red-gold)
R8 - 10kW5% ¼W Resistor
(brown-black-orange-gold)
R5 - 3.9kW5% ¼W Resistor
(orange-white-red-gold)
R9 - 100kW5% ¼W Resistor
(brown-black-yellow-gold)
R1 - 620W5% ¼W Resistor
(blue-red-brown-gold)
J1 - 4” Black Wire 22ga.
J3 - 2.5” Black Wire 22ga.
(see Figure C)
U1 - 16-pin IC Socket
U1 - XR-2206 IC
(see Figure D)
R6 - 200W5% ¼W Resistor
(red-black-brown-gold)
S2 - Slide Switch DPDT
R4 - 22kW5% ¼W Resistor
(red-red-orange-gold)
C7 - 10mF16V Electrolytic
(see Figure A)
C8 - 10mF16V Electrolytic
(see Figure A)
J2 - 2.5” Black Wire 22ga.
(see Figure C)
(+)
( )
or
Figure C
Cut two2.5”, three 3”, and one 4”
wire and strip 1/4” of insulation off
of both ends of the wires. Solder
these wires to the points J1, J2,
J3, J4, J7, and J8.

Figure Ea Figure Eb
Mount the pot down flush with the PC
board. Solder and cut off excess leads.
-5-
ASSEMBLE COMPONENTS TO THE PC BOARD
INSTALL COMPONENTS TO FRONT PANEL
Install the jack to the panel with the side lug facing the direction shown in Figure H. Fasten the jack in place
with the round nut from the front side of the panel.
R2 - 10kWPotentiometer
Hex Nut 7mm
(see Figures Ea & Eb)
S1 - 6 position Rotary Switch
(see Figure F)
R3 - 100kWPotentiometer
(see Figures Ea and Eb)
Battery Snap
(see Figure G)
Figure G
Thread the battery snap wires
through the hole in the PC board
from the solder side as shown.
Solder the red wire to the BT+
point and the black wire to the BT--
point on the PC board.
Red Wire (BT+)
BlackWire (BT--)
Red Wire (BT+)
Black Wire (BT--)
Cut off tab
Figure H
Round Nut
BackSide
of Panel
Side Lug
Jack
Put a 7mm hex nut onto the pot as
shown.
Figure F
Mount down
flush with PC
board.
Cut off tab

Install the colored binding posts to the panel as shown in Figure I.
Use the hardware shown in the figure. Make sure that the small nut
is tight.
WIRING (See Figure J and Ja)
Solder the wire from hole J1 on the PC board to the first yellow
binding post as shown.
Solder the wire from hole J2 on the PC board to the second yellow
binding post as shown.
Solder the wire from hole J3 on the PC board to the black binding
post as shown.
Solder the wire from hole J4 on the PC board to the lower lug (A) of
the jack as shown.
Solder the wire from hole J7 on the PC board to the upper left lug (C)
on the jack as shown.
Solder the wire from hole J8 on the PC board to the upper right lug
(B) on the jack as shown.
-6-
Figure I
Nut
Lockwasher
Binding Post
Yellow
Yellow
Black
Backside of
Panel
Small Nut
Figure J
Attach the wires
to the lugs before
soldering.
(B)
(C)
Side Lug (A)
Figure JA
Wire from
Point J3
Wire from
Point J2
Wire from
Point J1
Wire from
Point J4
Wire from
Point J7
Wire from
Point J8
Component Side
of PC Board

-7-
Install the handle as shown in Figure L.
Cut twopieces of weather stripping. Remove the protective backing and place a piece of weather strip on
the top panel in the location shown in Figure L. Then, place the other piece on the case in the location shown.
8mm x 14mm Washers
7mm Hex Pot Nuts
9mm Hex Switch Nut
Figure K
9mm x 15mm Flat Washer
4-40 x 1/4”
Screws
Spacers
Weather Strip
Weather Strip
The battery should fit like this.
PC Board
Panel
Bottom Case
Battery
Figure L
Handle
FINAL ASSEMBLY
Fit the panel onto the PC board assembly. Be sure that all switches and pots come through the holes in the
panel as shown in Figure K.
Place the washers onto their locations as shown in Figure K, being careful to check the sizes. Then, tighten
the hex nuts onto the potentiometers and rotary switch noting their size as shown in Figure K. Finally, fasten
the spacers onto the top panel with two 4-40 x 1/4” black screws.

-8-
Attach the battery snap to the battery. Insert the PC board assembly with the panel and battery into the case
(as shown in Figure L). Insert two 4-40 x 1/4” screws into the bottom case in positions shown in Figure M
and tighten in place.
Turn the shafts on the two potentiometers and rotary switch fully counter-clockwise. Push the three knobs
onto the shafts so that the line on the knob is on the point as shown in Figure N.
TESTING THE FG-500 FUNCTION GENERATOR
The unit may be tested by following the 4 steps listed below. Should any of these tests fail, refer to the
Troubleshooting Guide.
1) Set the switches and pots as follows:
On/Off On
Range 10
Frequency Maximum (clockwise)
Amplitude Maximum (clockwise)
Sine/Triangle Set Sine/Triangle switch to Sine position
4-40 x 1/4” Screws
Figure M
Figure N

-9-
In each of the following steps, start with the switch and pots as shown on the previous page.
2) OUTPUT WAVEFORMS
Connect an oscilloscope probe to the square wave output. You should see about 8V peak to peak square wave
of a little over 15Hz. Connect the oscilloscope probe to the sine/triangle wave output. You should see a sine
wave of approximately 3V peak to peak or greater. Set the Sine/Triangle switch to the Triangle wave position.
You should see a triangle waveform of approximately 3V peak to peak or greater. In both sine and triangle
waves, the frequency is also a little over 15Hz.
3) FREQUENCY CONTROLS
6range settings, vary the FREQUENCY pot from max to min and check that the frequency varies according to
Table 1 on page 11 or greater.
4) AMPLITUDE CONTROLS
Set the switch and pots as in Step 1. Connect the oscilloscope to the sine/triangle wave output and vary the
AMPLITUDE pot. The sine wave amplitude should vary from near zero to approximately 3V peak to peak or
greater.
TROUBLESHOOTING GUIDE
A) NO SINE/TRIANGLE OR SQUARE WAVE OUTPUT
1) Check the soldering on switch S3.
2) Check battery and battery snap.
3) Checkjack.
4) Check the soldering on IC U1.
5) Check for +9V on IC1 pin 4.
6) Checkthat U1 is not installed backwards.
7) Check all of the values and soldering on R1, R2, R3, R4, R5, R7, R8, R9, C8, and C9.
B) WRONG FREQUENCY ON ANY RANGE SETTING
1) This indicates a wrong value capacitor in the bad range position.
C) SINE/TRIANGLE SWITCH DOESN’T WORK
1) Checkthe soldering on switch S2 and R6.
2) Check the value of R6.
3) Check pin 13 and 14 of U1.
D) AMPLITUDE CONTROL DOESN’T WORK
1) Check the soldering on R3, R7, R8, R4 and R9.
2) Checkthe values of the above mentioned components.
E) FREQUENCY CONTROL DOESN’T WORK
1) Check the soldering on R1 and R2.
2) Checkthe values of the abovetworesistors.

-10-
FUNCTIONAL DESCRIPTION
The FG-500 is a function generator integrated circuit capable of producing high quality sine, triangle, and square
waves of high stability and accuracy. A picture of each waveform is shown below:
THEORY OF OPERATION
The heart of the FG-500 Function Generator is the
XR-2206 monolithic function generator integrated
circuit. The XR-2206 is comprised of four main
functional blocks as shown in the functional block
diagram (Figure 1). They are:
• A Voltage Controlled Oscillator (VCO)
•An Analog Multiplier and Sine-shaper
•Unity Gain Buffer Amplifier
•Aset of current switches
The VCO actually produces an output frequency
proportional to an input current, which is produced
byaresistor from the timing terminals to ground.
The current switches route one of the currents to the
VCO to produce an output frequency. Which timing
pin current is used, is controlled by the FSK input
(pin 9). In the FG-500, the FSK input is left open,
thus only the resistor on pin 7 is used. The
frequency is determined by this formula:
fo=1/RC Hz
where fois the frequency in Hertz
R is the resistance at pin 7 in Ohms
Cis the capacitance across pin 5 and 6 in Farads
Note that frequency is inversely proportional to the value of RC. That is, the higher the value of RC, the smaller
the frequency.
The resistance between pins 13 and 14 determine the shape of the output wave on pin 2. No resistor produces
atriangle wave. A 200Wresistor produces a sine wave.
Sine Wave Triangle Wave Square Wave
FUNCTIONAL BLOCK DIAGRAM
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
Figure 1
Current
Switches
VCO
Multiplier
and
Sine
Shaper
+1
AM Input
Sine/Saw
Output
Mult. Out
V+
Timing
Capacitor
Timing
Resistor
Symmetry
Adjust
Waveform
Adjust
Ground
Sync
Output
Bypass
FKS
Input

-11-
CONTROLS
RANGE SWITCHES
Six ranges of frequency are provided by the range switch as shown in Table 1.
Table 1
SINE/TRIANGLE SWITCH
This SINE/TRIANGLE Switch selects the waveform, sine wave or triangle wave, sent to the SINE/TRIANGLE
output terminal.
FREQUENCY MULTIPLIER
The multiplier is a variable control allowing frequency settings between fixed ranges. The ranges are as shown
in Table 1.
AMPLITUDE CONTROL
The Amplitude Control provides amplitude adjustment from near 0 to 3V or greater for both sine and triangle
waveforms.
ON/OFF SWITCH
The ON/OFF Switch turns the power to the FG-500 on or off.
POWER JACK
This jackallows the FG-500 to be powered from an external power source of 9V to 18VDC. Putting a plug into
the jack disconnects the internal 9V battery.
OUTPUT TERMINAL
The output marked SINE/TRIANGLE provides the sine and triangle waveforms. The output marked SQUARE
WAVE provides the square wave. The output marked GND provides the ground for all output waveforms.
POSITION TYPICAL FREQUENCY RANGE
1 1Hz - 15Hz
2 10Hz - 150Hz
3 100Hz - 1.5kHz
4 1kHz - 15kHz
5 10kHz - 150kHz
6 100kHz - 1MHz

-12-
SCHEMATIC DIAGRAM

-13-
QUIZ
1) The heart of the FG-500 Function Generator is the _________ monolithic function generator integrated
circuit.
2) The XR-2206 is comprised of four main blocks. They are ____________________,
____________________, ____________________, and ____________________.
3) The VCO actually produces an output frequency proportional to an input ________________.
4) The current switches route one of the currents to the VCO to produce an output __________.
5) The frequency is determined by the formula _______________.
6) Frequency is inversely proportional to the value of _____________.
7) The resistance between pins 13 and 14 determine the shape of the __________ wave on pin 2.
8) No resistor produces a __________ wave.
9) A200Wresistor produces a ___________ wave.
10) The six ranges of frequency provided by the range switch are:
________ to ________. ________ to ________.
________ to ________. ________ to ________.
________ to ________. ________ to ________.
Answers: 1) XR-2206; 2) A Voltage Controlled Oscillator, An Analog Multiplier and Sine Shaper, Unity Gain Buffer
Amplifier and A Set of Current Switches; 3) Current; 4) Frequency; 5) 1/RC; 6) RC; 7) output; 8) triangle; 9) sine;
10) 1Hz to 15Hz, 10Hz to 150Hz, 100Hz to 1.5kHz, 1kHz - 15kHz, 10kHz - 150kHz, 100kHz - 1MHz.

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Elenco®Electronics, Inc.
150 Carpenter Avenue
Wheeling, IL 60090
[phone]
Website: www.elenco.com
e-mail: [e-mail]