Textbook in PDF format A foundational yet practical understanding of electronics is central for researchers working on experiments in modern scientific labs. However, students in the sciences are often given minimal training in electronics, leading to gaps in understanding of debugging, testing, automation, or various other crucial skills. This textbook offers a one-semester, lab-based introduction to analog and digital electronics, combining theory and practical knowledge to prepare readers to engage with electronic systems of cutting-edge scientific experiments. Beginning with fundamentals such as basic DC and AC circuits, transistors and amplifiers, this book then tackles important practical issues such as high-speed signals in cables and oscilloscope measurements. We then move on to critical modern electronics tools such as Arduinos and field-programmable gate arrays (FPGAs). Each chapter contains theoretical lecture material which are supplemented with key lab experiments to perform, totaling about 14 weeks of instruction. The material assumes only a high-school level knowledge of mathematics, with no requirement beyond introductory physics concepts. This book is accessible to undergraduates and graduate students, but it could also be used by students and enthusiasts of any age whether in school or industry