PHOBOS GERMANIUM FUZZ
11
DIODES
PART VALUE
D1
1N5817
D2
1N34A (Ge)
Z1
1N4742A
Next, you’ll populate the diodes. The 1N5817 is black with a silver stripe, while the 1N4742A is orange
with a black stripe. The 1N34A germanium is not labeled, but is significantly larger than the other two.
Diodes are polarized, so make sure to identify the polarity band (which indicates the
cathode
, or negative
side) and match the band to the footprint on the PCB. The germanium diode has several colored stripes,
but the cathode is indicated by a thick black stripe.
Precautions with germanium diodes
Germanium diodes are fragile and require more care than the other components. Make sure to observe
the following precautions when working with them.
• To prevent stress on the glass body of the diode, when bending the leads,
use needle-nose pliers or tweezers to clamp the lead as close to the body as
possible while you bend it down. The bend should be about 0.05–0.08” from
the body of the diode, so use pliers with a very narrow tip.
• Old-stock diodes can sometimes develop corrosion on the leads. It’s recommended to use
sandpaper or a small file to gently rough up the leads where they will make contact with the
solder. This will make adhesion much easier.
• Be quick when soldering. Germanium diodes can easily be damaged by overheating. Limit contact
with the soldering iron to 1-2 seconds maximum. If you don’t have a good solder joint, wait a
minute or two for it to cool before trying again.
