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WRM-4
3.3. Preparation
Put the sorted components in front of you on your workbench.
The separate electronic components have the following special features you should take into
account in assembling:
Resistors
Resistors reduce current.
The value of resistors for smaller power ratings is indicated through colour rings.
Every colour stands for another figure.
Carbon film resistors have 4 colour rings. The 4th ring (given in brackets here)
indicates the tolerance of the resistor (gold = 5 %).
Value:
Colour rings:
1 k
brown - black - red (gold)
10 k
brown - black - orange (gold)
47 k
yellow - violet - orange (gold)
470 k
yellow - violet - yellow (gold)
Diodes
Diodes allow the current to pass through in one direction only (forward direction),
simultaneously the voltage is reduced by 0,3 to 0,8 V. Exceeding of the limit
voltage always will destroy the diode, and allow current to flow in the reverse
direction.
The diode type is printed on the body. Diodes must be mounted in a given
direction. The negative end is marked with a ring. This is shown in the PCB
layout.
Ceramic capacitors
Among other things ceramic capacitors are used for filtering interference voltages
or as frequency determining parts. Ceramic capacitors are not polarized.
Normally they are marked with a three-digit number which indicates the value
coded:
Number: Value:
103
10 nF
104
100 nF
Electrolytic capacitors
Electrolytic capacitors are often used to store energy. In contrast to ceramic
capacitors they are polarized. One of the two leads is marked with a minus sign
which indicates the mounting orientation. The value is given on the casing.
Electrolytic capacitors are available with different voltage sustaining capabilities.
Using an electrolytic capacitor with a voltage sustaining capability higher than
required is always possible.
Assembling the kit | 9