Output circuits

1.3 Sensing circuits

1.5 Switching circuits

Output circuits

  1. Output devices

    Device Function
    Buzzer Produces sound
    Lamp Produces light
    Most are filament lamps that burn out after around 1000 hours of continuous use
    Light-emitting diode (LED) Produces light more efficiently than a lamp, so does not get so hot, in a larger variety of colours, and lasts longer, around 100,000 hours of continuous use
    Motors Produces movement
    Solenoid Produces a magnetic field

  2. Current-limiting resistor

    1. If a component drops (virtually) no resistance, if no other components are wired in series, a very high current, effectively infinite, flows through the component, breaking it, so a resistor must be wired in series in order to limit the current
    2. For example: an LED drops 2 V and the standard maximum current used to drive it is 350 mA
    3. The current-limiting resistor has a resistance calculated using Ohm’s law: e.m.f. - 2 V350 mA