4- A single transistor can be used to build which of the following digital logic gates? d) NAND gates a) AND gates b) OR gates c) NOT gates 5- The diagram below is a block diagram of an electronic circuit. The parts of the circuit are labeled X, Y and Z Part X Heat sensor Light sensor Part Y Relay Part Z a-Name the two types of logic gate used in the circuit above: 1... b- Give an electrical device which could be used as: 1. The heat sensor Heater *********** ......... 2. The light sensor...... 2. c-Which part of the circuit, X, Y or Z, is? The processor? The input device(s)? The output device(s)?.. d- The heat sensor is ON when it is hot and OFF when it is cold. The light sensor is ON when it is light and OFF when it is dark. Explain what happens in each part of the circuit when it is both cold and dark.