Ron Stull of CUI explains what power factor is, how it affects efficiency calculations and how it is measured With today’s concentration on energy savings, design engineers need to know with increasing accuracy what their ac-dc power converter efficiency is. Measuring the ratio of output power to input power is simple for dc-dc converters, but […]
FAQ
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 […]
Power-supply overvoltage protection, Part 2: Clamps
Part 1 of this FAQ discussed the context of overvoltage protection and crowbars which provide OVP. This part will look at clamps for OVP use. Q: What does the clamp do? A: A clamp conducts just-enough current to maintain the voltage across it at a safe, desired value when the transient is above the clamp’s […]
Understanding and debugging antenna designs
Any conductive body functions intentionally or otherwise as an antenna in the presence of an oscillating electromagnetic field. This radiation excites free electrons in the conductor, and if a load is connected, a small but measurable current will flow in that load. By the same token, if oscillating voltage is applied to a conductor, it […]
Power-supply overvoltage protection, Part 1: Crowbars
Engineers who deal with power supplies (as most eventually do) often see the circuit-protection terms “crowbar” and “clamp.” No, there are no references to items purchased at the local hardware store, but they are essential “hardware” elements, meaning autonomous circuit components and functions with no related software. They are used to provide protection to a […]
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 […]
FAQ: Piezoelectric motors, Part 2: drive circuits
Unlike better-known electromagnetic motors, the widely used piezoelectric-based motor/actuator provides precise, repeatable linear motion over short distances, and requires a voltage drive rather than a current drive. Part 1 of this FAQ looked at the moving piezoelectric element of the actuator. Part 2 looks at their drive requirements, which are very different than those of […]