26 (d) A light-emitting diode (LED) is connected to the output from a logic gate circuit.
LED lights up
The LED is removed and a 230 V bulb is connected to the same output from the logic gate circuit. 230 V bulb does not light up
To make the 230 V bulb light up a relay is needed. The relay must be connected between the logic gate circuit and a separate circuit containing the 230 V bulb. Explain why a relay is needed and how it protects the logic gate circuit. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [2] [Total: 7]
Š OCR 2014