Frequency synthesizers of various architectures, made possible by IC technology, are a key building blocks for applications which must accurately tune multiple channels, and hop from one frequency to another while using a single signal source such as a crystal oscillator. When you want to tune a desired radio station — AM or FM — […]
Wheatstone bridge, Part 2: Additional considerations
Part 1 of this FAQ explained the basic principle of the Wheatstone bridge. This part will take the bridge configuration into modern applications and go beyond basic resistance measurements. Q: All this measurement via changing resistance or by measuring current seems very slow or static; how does it fit into today’s electronics? A: First, many […]
Wheatstone bridge, Part 1: Principles and basic applications
Although the electronics industry is relentlessly driven by advances in materials, components, and architectures, the “new” obviously also builds on the “old” and often still uses it, albeit in new guises. There’s still a viable place and need for old devices such as the transformer, solenoid, relay, and Wheatstone bridge. This FAQ will look at […]
Blood oxygen meters, Part 2: IC implementations
It is now trivial and non-invasive to measure blood-oxygen saturation SpO2, thanks to LEDs, algorithms, and ICs for pulse oximetry — it’s a very long way from having to draw blood and send it out for assessment. Part 1 of this FAQ discussed the principle of the non-invasive, light-based pulse-oximetry systems for reading blood-oxygen saturation […]
Blood oxygen meters, Part 1: Background and principles
It is now trivial and non-invasive to measure blood-oxygen saturation SpO2, thanks to LEDs, algorithms, and ICs for pulse oximetry — and it’s a very long way from having to draw blood and send it out for assessment. Just a few decades ago, determining the vital medical parameter known as blood oxygen level — formally […]
Quartz crystals and oscillators, Part 2: Advanced crystals
Part 1 of this FAQ established the context for the quartz crystal as the core of an oscillator whether used as a system clock or as a frequency-setting element in a tuning circuit. This part looks at the achievable performance, the factors that affect it, and what can be done for highest performance. Q: What […]
Quartz crystals and oscillators, Part 1: Crystal basics
An oscillator or clock function is key to nearly all electronic circuits, and in most (but not all) cases, the heart of this oscillator circuit is a tiny piece of quartz, called the crystal blank or slab. It’s easy and commonplace to think of the crystal as a simple component, but as with most components, […]
GPS, Part 2: Implementation
Part 1 of this FAQ looked at the basic principles of the GPS system. Part 2 looks at some hardware circuitry used to implement a GPS receiver as well as the unappreciated role that Einstein’s Theory of Special Relativity plays in providing an accurate GPS. Q What are the key elements of a GPS receiver? […]
GPS, Part 1: Basic principles
The Global Positioning System (GPS) is a worldwide, RF wireless-based system for determining where you are anywhere in the Earth’s surface if there is line-of-sight visibility to at least four of its orbiting satellites. The availability of GPS since its inception a few decades ago has not only enabled products and features which were simply […]
e-Fuses, Part 2: Building or buying an e-Fuse
The electronic fuse is a powerful and versatile tool in the designer’s kit, but building one requires careful selection of the core amplifier; IC embodiments solve the problem. Part 1 of this FAQ looked at the basic structure of the electronic fuse or e-fuse. This part looks at the requirements on the current sense amplifier […]