The aim of this module is to further understanding of design techniques for transistor-based analogue circuits, using transistor amplifiers as a vehicle for this. Standard high-frequency models are introduced for transistors. This approach enables amplifier operation to be understood and analysed at all signal frequencies, starting with a review of mid-band operation, followed by low and high frequency operation. The design of single-stage amplifiers of various circuit topologies, two-stage amplifiers, the differential pair and two stage opamp are explored. Finally the origins and effect of noise in electronic circuits is introduced.