Vectronics VEC-4001K User Manual

VEC-4001K Owner’s Manual Professional Function Generator

INTRODUCTION

This easy-to-build professional grade function generator kit provides precision sine, square, and triangle waveforms from 1 Hz to 1 MHz in six decade ranges. Waveform amplitude is continuously adjustable from 0 to 12-Volts peak-topeak. DC offset is adjustable from -6 to +6 VDC. Output impedance is 400 Ohms, with short-circuit output protection. Simple-to-follow step-by-step instructions guide you through assembly and alignment. Cir cuitry is construct ed on a rugged professional-quality glass-epoxy PC bo ard with a solder mask and silk-screened component-placement legend. Your kit uses only high-quality components througho ut, and it co mes co mplete with a sturd y molded cab ine t and silk-screened aluminum front panel. AC power adapter included.

TOOLS AND SUPPLIES

Construction Area: Kit construction requires a clean, smooth, and well-lighted area where you can easily organize and handle small parts without losing them. An inexpensive sheet of white poster board makes an excellent construction surface, while providing protection for the underlying table or desk. Diffused overhead lighting is a plus, and a supplemental high-intensity desk lamp is especially helpful for close-up work. Safety is always important! Use a suitable high-temperature stand for your soldering iron, and keep the work area free of clutter.

Universal Kit-building Tools: No special tools are required to complete this kit beyond common items normally used for bench construction. We recommend the following:

! Soldering Iron (grounded-tip and temperature-controlled preferred) ! High-temperature Iron Holder with Cle aning Sponge ! Solder, 60/40 or 37/63 with rosin or "no-clean" flux (.031" dia. is good size) ! Needle Nose Pliers or Surgical Hemostats ! Diagonal Cutters or "Nippy Cutters" ! Solder Sucker (squeeze or vacuum pump type), or Desoldering Braid ! Bright Desk Lamp ! Magnifying Glass

VEC-4001K Owner’s Manual Professional Function Generator

BEFORE YOU START BUILDING

Experience shows there are four common mistakes builders make. Avoid these, and your kit will probably work on the first try! Here's what they are:

1. Installing the Wrong Part: It always pays to double-check each step. A 1K

and a 10K resistor may look almost the same, but they may act very differently in an electronic circuit! Same for capacitors--a device marked 102 (or .001 uF) may have very different operating characteristics from on marked 103 (or .01uF).

2. Installing Parts Backwards: Always check the polarity of electrolytic

capacitors to make sure the positive (+) lead goes in the (+) hole on the circuit board. Transistors have a flat side or emitter tab, and ICs have a notch or dot at one end indicating the correct direction of insertion. Diodes are polarized with a band to indicate the cathode end. LED polarity is coded by lead length. Always double-check--especially before applying power to the circuit!

3. Faulty Solder Connections: Inspect for cold-solder joints and solder

bridges. Cold solder joints happen when you don't fully heat the connection-or when metallic corrosion and oxide contaminate a component lead or pad. Solder bridges form when a trail of excess solder shorts pads or tracks together (see Soldering Tips below).

4. Omitting or Misreading a Part: This is easier to do than you might think!

Always double-check to make sure you completed each step in an assembly sequence.

Soldering Tips: Cleanliness and good heat distribution are the two secrets of professional soldering. Before you install and solder each part, inspect leads or pins for oxidation. If the metal surface is dull, sand with fine emery paper until shiny. Allow the tip of your iron to contact both the lead and pad for about one second (count "one-thousand-one") before feeding solder to the connection. Surfaces must become hot enough for solder to flow smoothly. Feed solder to the opposite side of the lead from your iron tip--solder will wick around the lead toward the tip, wetting all exposed surfaces. Apply solder sparingly, and do not touch solder directly to the hot iron tip to promote rapid melting. Keep a damp sponge handy to wipe your so ldering tip on. This removes excess solde r, and keeps the tip properly tinned. If the iron is going to sit idling for long periods, wipe the tip, add some fresh solder, and unplug the iron.

Desoldering Tips: If you make a mistake and need to remove a part, follow these instructions carefully! First, grasp the component with hemostats or needle-nose pliers. Heat the pad beneath the lead you intend to extract, and pull gently. The lead should come out. Repeat for the other lead. Solder may fill in

VEC-4001K Owner’s Manual Professional Function Generator

behind the lead as you extract it--especially if you are working on a double-sided board with pla te-through holes. Should this hap pen, try heating the pad again and inserting a common pin into the hole. Solder won't stick to the pin's chromium plating. When the pad cools, remove the pin and insert the correct component. For ICs or multiple-pin parts, use desoldering braid to remove excess solder before attempting to extract the part. Alternatively, a low-cost vacuum-bulb or spring-loaded solder sucker may be used. Parts damaged or severely overheated during extraction should be replaced rather than reinstalled.

Work Habits: Kit construction requires the ability to follow detailed instructions and, in many cases, to perform new and unfamiliar tasks. To avoid making needless mistakes, work for short periods when you're fresh and alert. Recreational construction projects are more informative and more fun when you take your time. Enjoy!

Sorting and Reading Resistors: The electrical value of resistors is indicated by a color code (shown below). You don't have to memorize this code to work with resistors, but you do need to understand how it works:

Resistor Color Code

Black = 0 (tens) 1st Digit 2nd Digit Multiplier

Tolerence

(gold or silver)

When you look at a resistor, check its multiplier code first. Any resistor with a black multiplier band falls between 10 and 99 ohms in value. Brown designates a value between 100 and 999 ohms. Red indicates a value from 1000 to 9999 ohms, which is also expressed as 1.0K to 9.9K. An orange multiplier band designates 10K to 99K, etc. To inventory resistors, first separate them into groups by multiplier band (make a pile of 10s, 100s, Ks, 10Ks, etc.). Next, sort each group by specific value (1K, 2.2K, 4.7K, etc). This procedure makes the inventory easier, and also makes locating specific parts more convenient later on during construction. Some builders find it especially helpful to arrange resistors in ascending order along a strip of double-sided tape.

Reading Capacitors: Unlike resistors, capacitors no longer use a color code for value identification. Instead, the value, or a 3-number code, is printed on the body.

Brown = 1 (hundreds)

Red = 2 (K)

Orange = 3 (10K)

Yellow = 4 (100K)

Green = 5 (1Meg)

Blue = 6

Violet = 7

Gray = 8

White = 9

Silver = 10%

Gold = 5%

VEC-4001K Owner’s Manual Professional Function Generator

Value Code

10 pF = 100 100 pF = 101 1000 pF = 102

.001 uF = 102*

.01 uF = 103 .1 uF = 104

As with resistors, it's helpful to sort capacitors by type, and then to arrange them in ascending order of value. Small-value capacitors are characterized in pF (or pico-Farads), while larger values are labeled in uF (or micro-Farads). The transition from pF to uF occurs at 1000 pF (or .001 uF)*. Today, most monolithic and disc-ceramic capacitors are marked with a three-number code. The first two digits indicate a numerical value, while the last digit indicates a multiplier (same as resistors).

Electrolytic capacitors are always marked in uF. Electrolytics are polarized devices and must be oriented correctly during installation. If you become confused by markings on the case, remember the uncut negative lead is slightly shorter than the positive lead.

Diodes: Diodes are also polarized devices that must be installed correctly. Always look for the banded--or cathode--end when installing, and follow instructions carefully.

Multilayer

(270 pF)

271

Ceramic Discs

(.001 uF) (.1 uF)

102

Cathode

104

Electrolytic

1 uF

1uF

35V

(shorter Lead)

Diode

Transistors: If transistors are installed incorrectly, damage may result when

power is applied. Transistors in metal cases have a small tab near the emitter lead to identify correct positioning. Semiconductors housed in small plastic cases (TO-92) have an easily-identified flat side to identify mounting orientation. Many specialized diodes and low-current voltage regulators also use this type packaging. Larger plastic transistors and voltage regulators use a case backed with a prominent metal tab to dissipate heat (T-220). Here, orientation is indicated by the positioning of the cooling tab.

LED

VEC-4001K Owner’s Manual Professional Function Generator

Metal Can Device Plastic Device Tab-cooled Device

Emitter

Flat Side

Integrated Circuits: Proper IC positioning is indicated by a dot or square

marking located on one end of the device. A corresponding mark will be silkscreened on the PC board and printed on the kit's parts-placement diagram. To identify specific IC pin numbers for testing purposes, see the following diagram. Pin numbers always start at the keyed end of the case and progress counterclockwise around the device, as shown:

8 7 6 5

Installation

Key

Installation

Key

1 2 3 4

Pin Numbers

Metal Tab

VEC-4001K Owner’s Manual Professional Function Generator

PARTS LIST

Your kit should contain all of the parts listed below. Please identify and inventory each item on the checklist before you start building. If any parts are missing or damaged, refer to the manual's warranty section for replacement instructions. If you can't positively identify an unfamiliar item on the basis of the information given, set it aside until all other items are checked off. You may then be able to identify it by process of elimination. Finally, your kit will go together more smoothly if parts are organized by type and arranged by value ahead of time. Use this inventory as an opportunity to sort and arrange parts so you can identify and find them quickly.

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Qty Part Description Designation VEC P/N

1 51 ohm resistor

(green-brown-black)

2 100 ohm resistor

(brown-black-brown)

1 680 ohm resistor

(blue-gray-brown)

1 1K resistor (brown-

black-red)

8 1.6K resistor (brown-

blue-red)

1 2K resistor (red-

black-red)

2 3K resistor (orange-

black-red)

4 12K resistor (brown-

red-orange)

2 22K resistor (red-red-

orange)

1 24K resistor (red-

yellow-orange)

2 27K resistor (red-

violet-orange)

1 1K trimpot (102) R10 133-3100

6 5K trimpot (502) R4-R9 133-3500

3 10K 24-mm

potentiometer (103)

R16 100-1510

R25,R26 100-2100

R15 100-2680

R19 100-3100

R28-R35 100-3160

R17 100-3200

R13,R21 100-330

R11,R12,R14,R

100-4120

20 R24,R27 100-4220

R18 100-4240

R22,R23 100-4270

R1,R2,R3 162-4100-

VEC-4001K Owner’s Manual Professional Function Generator

1 680 pF disc ceramic

capacitor (681)

.001 µF disc ceramic

C20 200-0680-

C22,C23 200-1100

capacitor (102)

.1 µF disc ceramic capacitor (104)

C3,C4,C5,C6,C 9,C10,C13,C14

200-3100

,C25,C26, C27,C28,C29

.0068 µF polyester

C19 230-1680

ceramic capacitor

.082 µF polyester

C18 230-2820

ceramic capacitor

1 µF tantalum capacitor

1 µF electrolytic capacitor

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Qty Part Description Designation VEC P/N

10 µF electrolytic capacitor

100 µF electrolytic capacitor

2200 µF electrolytic capacitor

2 1N4148 switching diode D3,D4 300-4148

2 1N4007 rectifier diode D1,D2 300-4007

1 2N3904 npn transistor Q1 305-3904

1 2N3906 pnp transistor Q2 305-3906

1 78L05 voltage

C21,C24 272-4100-

C17 270-4100-

C16 270-5100-

C7,C8,C11,C12 ,C15

270-61001

C1,C2 270-7220-

U6 307-7805L

regulator IC

1 78L12 voltage

U4 307-7812L

regulator IC

1 79L05 voltage

U7 307-7905L

regulator IC

1 79L12 voltage

U5 307-79L12

regulator IC

1 LM318 op-amp U2 324-0318

VEC-4001K Owner’s Manual Professional Function Generator

1 LM358 dual op-amp U3 324-0358

1 MAX038CPP function

U1 325-0038

generator IC

1 Six-position rotary

SW2 500-1008

switch

1 2P2T slide switch SW1 501-1003

1 4P4T slide switch SW3 501-1043

1 2.1-mm coaxial power

J1 601-6121

jack

1 Binding post, red J2 606-0003

1 Binding post, black J3 606-0004

2 IC socket, 8 pin 625-0008

1 IC socket, 20 pin 625-0020

1 Switch-style knob 760-0036

3 Control knob 760-0033

6 6" hook-up wire, black 871-2422-

0600

6 6" hook-up wire, red 871-2422-

0600

5 6" hook-up wire,

yellow

1 PC board, single-sided 861-

871-2444-

0600

VEC4001

1 Instruction manual 925-

VEC4001K

1 Case, plastic 840-0524

1 Faceplate, VEC-4001 804-

VEC4001

2 Screw, 2-56 x 3/8" 652-0375

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Qty Part Description Designation VEC P/N

2 Nut, 2-56 705-0256

4 Screw, 4-40 x 1/4" 654-0250B

4 Nut, 4-40 705-0440

12 Screw, black, 6-32 x

656-0250B

1/4"

+ 21 hidden pages