ABOVE-THE-BOARD TERMINATION. - Above-the-board termination is accomplished through the use of terminals or posts. Terminals are used for a variety of reasons. The type of terminal depends on its use. Although many configurations are used, all terminals fall into one of the five categories covered in this section [figure 3-8, views (A) through (E)].

Figure 3-8A. - Terminals. PIN AND TERMINALS

Figure 3-8B. - Terminals. HOLLOW

Figure 3-8C. - Terminals. HOOK TERMINALS

Figure 3-8D. - Terminals. PIERCED TERMINALS

Figure 3-8E. - Terminals. SOLDER CUP

PIN TERMINALS AND TURRET TERMINALS [view (A)] are single-post terminals, either insulated or uninsulated, solid or hollow, stud or feed-through. Stud terminals protrude from one side of a board; feed-throughs protrude from both sides. BIFURCATED OR FORK TERMINALS [view (B)] are solid or hollow double-post terminals. HOOK TERMINALS [view (C)] are made of cylindrical stock formed in the shape of a hook or question mark.

PERFORATED OR PIERCED TERMINALS [view (D)] describe a class of terminals that uses a hole pierced in flat metal for termination (e.g., terminal lugs). SOLDER CUP TERMINALS [view (E)] are a common type found on connectors.

Turret and bifurcated terminals are used for interfacial connections on printed circuit boards, terminal points for point-to-point wiring, mounting components, and as tie points for interconnecting wiring. Hook terminals are used to provide connection points on sealed devices and terminal boards.

Terminals used for wire or component lead terminations are normally made of brass with a solderable coating. Uninsulated terminals may be installed on an insulating substrate to form a terminal board. They may also be added to a printed circuit board or installed on a metal chassis. Insulated terminals are installed on a metal chassis.

ON-THE-BOARD TERMINATION. - On-the-board termination (figure 3-9) is also called LAP FLOW termination. In a lap flow solder termination, the component lead does not pass through the circuit board. This form of planar mounting may be used with both round and flat leads.

Figure 3-9. - On-the-board termination.

Q.6 What term is used to identify the procedure of connecting one side of a circuit board with the other?
Q.7 Name two types of through-hole termination.
Q.8 Turret, bifurcated, and hook terminals are used for what type of termination?
Q.9 When a lead is soldered to a pad without passing through the board, it is known as what type of termination?