SOLID STATE SWITCHES

1.6 SOLID STATE SWITCHES

  General

A solid state switching circuit is represented by a symbol that is sim­ilar to that used for a mechanically operated switch. An expression that is determined to be true (a logic 1) at the control lead actuates the switch. In more complicated systems, a logical expression adjacent to the symbol may be substituted for the control lead.

A. Figure 1

A logic "0" on the control line to a solid state switch causes the switch to go to the relaxed condition. On schematics, solid state switches are shown in the relaxed state.

B. Figure 2

A logic "1" on the control line causes the switch to actuate, enabling continuity between contacts 1 and 3.

Figure 1.2: Solid state switches