19
8. Transistors: There are three transistors in the Altura (Q1,Q2,Q3). These transistors are labeled
2N3904 (and possibly a few extra numbers or letters at the end). They look identical to the
voltage regulator (labeled L78L05), so please don’t get them mixed up -- otherwise your Altura
won’t work!
These transistors are shaped like a three-quarter moon. Notice the PCB graphics around the
holes have a similar shape to show you the correct orientation. Bend the leads out a little bit so
that they will fit in their holes and install the transistors in the board (39). Bend the leads out on
the other side of the board, solder and clip the leads (40,41).
39
40
41
INTEGRATED CIRCUITS (IC’S)
This kit contains four integrated circuit components. In general, IC’s are quite sensitive to static electricity
and could easily be damaged if they are exposed to moderately high voltages. Unfortunately, humans
are not sensitive to static electricity at these levels; in fact, most people can’t even feel a static discharge
less than around 1000 volts! So it is easy to damage these components without even knowing it. The
particular IC’s in this kit are only moderately sensitive to static discharge but it is still important to be
mindful of the following principles when handling them:
•
Make sure you are grounded, preferably by touching something grounded to the mains like the
metal chassis of a plugged-in amplifier, or a refrigerator. Next best would be a plumbing fixture.
At the very least you should touch a large conductive object like a metal desk or a filing cabinet.
•
When soldering IC’s, do not let the IC get too hot. Most chips have a temperature threshold
that shouldn’t be exceeded. As a rule of thumb don’t keep your iron on any leg longer than two
