User manual

English GBM-8
Page 30
Transistors
Transistors are current amplifiers which convert low signals into
stronger ones. They have three contacts. As they are polarized, they
have to be mounted in a certain direction.
BC-Types have a housing in form of a half cylinder (SOT-
housing). The cross section is shown in the PCB layout which
determines the mounting orientation.
Integrated circuits (ICs)
Depending on the type, ICs fulfil various tasks. They are
polarized and therefore have to be mounted in a certain
direction. The most common housing form is the so-called
"DIL"-housing, from which 4, 6, 8, 14, 16, 18 or more "legs"
(pins) are arranged along the long sides.
The mounting orientation is shown by a semicircular or circular marking
at the end of the housing, which is also shown on the PCB layout.
ICs are sensitive to damage during soldering (heat, electrostatic
charging). For that reason in the place of the ICs IC sockets are
soldered in, in which the ICs are inserted later. The mounting
orientation of the sockets is preset as well. The markings on the PCB,
the socket and the IC must lie on top of each other after mounting.
Opto couplers
Opto couplers are ICs, which work similar to laser beam switches. They
combine in one housing a light emitting diode and a photo transistor.
Their task is the transmittion of information without galvanic
connection. Normally they are in a DIL-housing with 4, 6 or 8 pins.
Terminal strips
Terminal strips are solder-in screw-type terminals. They provide a
solder-free and safe connection of the cables to the circuit, which can
still be seperated any time. When several terminal strips have to be
mounted side by side, they have to be put together before mounting.