"In 1979, we teamed up at DEST Corp. to design the first desktop OCR machine for scanning standard letter and legal pages with a linear Reticon stored-charge diode array. Internal to that sensor were two identical 2048-pixel diode strings. Light would deplete the diode pixel reset charge and be read as exposure versus time through a charge integrator. Because the CMOS diode-select shift registers created substantial charge injection noise, the dark string was differentiated with the active...

Field-effect transistors are foundational building blocks in modern electronics, but not all FETs are optimized for the same tasks. While MOSFETs dominate digital circuits, power management, and switching applications, JFETs continue to play a critical role in low-noise, high-impedance analog front ends. Understanding the strengths of each technology can help designers optimize system performance and avoid unnecessary tradeoffs. Understanding the Differences Both JFETs and MOSFETs are...

When engineers design front-end circuits for microphones, hydrophones, piezoelectric sensors, MEMS devices, and other high-impedance signal sources, noise is often the first specification they look at. And for good reason. Weak signals can easily be overwhelmed by amplifier noise, making low-noise devices essential for preserving signal integrity. But noise is only part of the equation. In many high-impedance applications, input capacitance can have an equally significant impact on overall...