Notes for construction:
We suggest you start by forming the resistor and diode leads first and then mounting and
soldering the ‘lowest’ components first.
Note that the tracks and pads on the PCB may have a protective clear lacquer which melts away
when soldered, so on these you will not need to clean the copper first. When soldering the
switch you will need to use quite a bit of heat to solder the legs properly but be careful not to
apply heat for too long. It is better to use a hotter iron for less time than a cool iron for longer!
The 555 timer integrated circuit is not especially static sensitive but should still be inserted last.
To protect the PCB pads you are strongly recommended NOT to fit and solder the coax cables
until you have constructed the wooden T support, aerials and mounted the metal case/tin.
Qty
1
1
1
4
2
2
4
1
1
1
1
Component Value
1K CR25 resistor (Brown Black Red Gold)
wire link (use one of the cut off resistor legs)
100K CR25 resistor (Brown Black Yellow Gold)
470R CR25 resistor (Yellow Violet Brown, Gold)
1N4148 / 1N916 equiv diodes (Note polarity line)
10nF capacitors (marked 103)
1nF capacitors (marked 102)
8 pin IC socket
2 Pole 3 position centre off toggle switch
PP3 Battery clip
NE555 Timer (fits into socket)
10nF
10nF
1nF
1nF
1nF
1nF
1k
100k
470
470
470
470
1N4148
1N4148
555 IC
1
wire link
Centre-off
DPDT toggle
Switch
Top (Component) View
Black
Red
Simple test
You may want to give your completed board a basic test before final assembly - if you have
access to an oscilloscope you can do this easily. After thoroughly checking all parts are located
and the battery clip is wired correctly connect a battery to the clips and an oscilliscope test probe
to pin 3 of the 555 IC and the ground lead of the scope probe to the Black/negative battery wire.
With the toggle switch in either the up or down position the scope should display a square wave
oscillation. The rest of the circuit is hard to test but as long as it has been assembled correctly it
should all work on completion
2
NARC DF100 PCB construction