An introduction to electronics at a level suitable for undergraduate students. The intent is to convey the fundamental ideas involved in electronics. The response of linear circuits to DC and AC voltage sources, and to step changes in voltage is first analyzed. Next the diode and transistor are introduced, along with the minimum of solid-state physics required to understand their operation. The use of a transistor as the key element in an amplifier is then described. The idea of negative feedback is introduced, and its advantages in improving the performance of amplifiers made evident. The book concludes with a discussion of operational amplifiers.