background image

 

 

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:  

1st Digit
2nd Digit
Multiplier

Tolerence

Black     =  0  (tens)
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%

Resistor Color Code

(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  sort  and 
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. 

Some VEC kits may contain molded chokes which appear, at first glance, 
similar to resistors in both shape and band marking.  However, a closer 
look  will  enable  you  to  differentiate  between  the  two--chokes  are 
generally larger in diameter and fatter at the ends than resistors.  When 
doing  your  inventory,  separate  out  any  chokes and consult the parts list 
for specific color-code information. 

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. 

Содержание VEC-821K

Страница 1: ...external speaker Eight poles of active IC filt ering gives super steep CW skirts for performance that few tunable filters can match interference is up to 60 dB down one octave away Razor sharp selecti...

Страница 2: ...eserves the right to make substitutions at any time In most cases these changes will be clearly noted in an addendum to the manual Defective Parts Today s electronic parts are physically and electrica...

Страница 3: ...List 11 Parts Placement Diagram 12 Step By Step Assembly 12 Phase 1 13 Phase 2 15 Phase 3 17 PC Board Inspection 20 Testing and Alignment 20 Operating Instructions 21 Receiver or Scanner Operation 21...

Страница 4: ...OOLS 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 whit...

Страница 5: ...ridges 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...

Страница 6: ...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 multi pin parts use desoldering braid to remove...

Страница 7: ...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 e...

Страница 8: ...evices 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 a...

Страница 9: ...d of the device A corresponding mark will be silk screened on the PC board and printed on the kit s parts placement diagram To identify specific IC pin numbers for testing purposes see the diagram bel...

Страница 10: ...1 5 6 ohm 1 2 watt resistor green blue gold R19 1 1K ohm resistor brown black red R2 1 1 8K ohm resistor brown gray red R1 6 24 3K ohm resistor red yellow orange red R5 R8 R10 R13 R14 R15 1 91K ohm re...

Страница 11: ...nything is missing or broken refer to the warranty instructions for replacing missing or damaged parts Note that part designators such as R1 C3 etc appear on a silk screened legend on the component mo...

Страница 12: ...orange Carefully bend the leads close to the resistor body as in Step 1 8 Insert R4 into its mounting holes so the resistor body rests against the board Solder in place and trim the leads 9 Locate res...

Страница 13: ...y rests against the board Solder in place and trim the leads 27 Locate resistor R15 This is 24 3K resistor red yellow orange red Carefully bend the leads close to the resistor body as in Step 1 28 Ins...

Страница 14: ...19 are made of a polystyrene type material Avoid overheating these components when soldering to prevent melting the capacitor body 1 Locate capacitor C12 1000pF The is a polystyrene capacitor and will...

Страница 15: ...r both leads in place making sure the capacitor remains seated Remove excess leads on the bottom side of the board with diagonal cutters 17 Locate capacitor C2 1uF This is a disc ceramic type capacito...

Страница 16: ...r glass type material This part will have a band on one end indicating the cathode end of the diode 27 Insert D2 into its mounting holes so the diode body rests against the board Be sure to observe th...

Страница 17: ...sure to orient the negative side of the capacitor properly Please refer to the section titled Parts Placement Figure 1 for correct orientation of C1 Once installed then solder in place and trim the ex...

Страница 18: ...d SPKR on the circuit board Solder in place and trim the excess lead 22 Take another 3 piece of insulated wire and insert one end into the hole silk screened G on the circuit board Solder in place and...

Страница 19: ...the right tools One very convenient item for freeing soldered in parts is a solder sucker This consists of a suction bulb or a spring loaded vacuum pump that draws molten solder away from the pad and...

Страница 20: ...wever in these positions the filter will let slightly more noise through but in some cases this may be desirable The best way to see which position works the best is to try it This way you can really...

Страница 21: ...en you switch to the 110 cutoff you will notice that the signal sounds cleaner than before You can now fine tune the radio tuning knob for the best received signal If using a communications receiver o...

Страница 22: ...ed please refer to the warranty instructions on the inside front cover THEORY OF OPERATION AND SPECIFICATIONS Circuit Description The VEC 821K uses two LM747 operational amplifier integrated circuits...

Страница 23: ...SCHEMATIC...

Страница 24: ...VEC 821K Instruction Manual Super CW Filter Kit 25 VEC 821K...

Отзывы: