Model-based system engineering (MBSE) uses digital twins, digital threads, and domain models to replace document-based information exchanges during the system development process. It is widely used with complex cyber-physical systems in aerospace, energy, healthcare, and transportation to define features, design, analyze and validate a system using virtual tools. For designers, MBSE is an expansive concept. […]
What materials can be used to make miniature antennas?
Many antennas are mechanically simple and electrically complex at the same time. Mechanically an antenna usually has only one or two components, a dielectric layer (which can be the entire antenna) and a conductive layer. This FAQ begins with a brief review of dielectric materials and their importance to antenna performance. It then explores developments […]
How do you use a current mirror?
Current mirrors are common circuits but are mostly invisible, except to designers of analog or mixed-signal integrated circuits who can use large numbers of current mirrors on a single chip. A current mirror copies a current through one active device (such as a BJT or MOSFET) by controlling the current in another active device. If […]
What can you make with MEMS technology?
Microelectromechanical systems (MEMS) has several names, including micro-electro-mechanical systems, and micromechatronic systems. In Japan, MEMS is called micromachines, while in Europe, it’s referred to as microsystem technology (MST). Whatever name that’s used, MEMS devices are made using components measuring from 1 to 100 μm (0.001 to 0.1 mm), with MEMS devices ranging from 20 μm […]
How do you make inductors with films, foils, and flat wires?
Wire wound structures are the most common, but far from only, way to make inductors for audio, power conversion, radio frequency (RF), and other applications. Inductors are key components in various circuits, and designers need to fully understand available options. This FAQ starts with a brief background on wirewound inductors and then digs into the […]
What are wirewound, carbon, and film resistors good for?
Resistance is one of the most basic concepts in electricity and electronics. And resistors are simple-looking devices. Given their apparent simplicity, the range of resistor types and their capabilities can be surprising. This FAQ looks at some common resistor types and tradeoffs between stability, precision, size, power handling, and so on. It briefly considers mounting […]
What’s the difference between equalizers?
Equalizers are used to alter the performance of signal chains. In some cases, that means linearizing signal chain performance. In other cases, equalizers are used to introduce nonlinearities. As a result, equalizer designs vary widely from simple passive circuits to complex multi-stage designs and active circuits. This FAQ reviews equalizer basics, looks at equalizers for […]
How does a precision rectifier work?
A precision rectifier, sometimes called a super diode, is an op amp circuit designed to behave like an ideal diode and is used in high-precision signal processing applications. It’s not a synchronous rectifier. The op-amp-based precision rectifier should not be confused with power MOSFET-based synchronous rectification. Because there is no diode voltage drop between the […]
What do you do with a bucket brigade device?
A bucket brigade device (BBD) is a discrete-time analog delay line using capacitors that has been replaced in most digital signal processing applications. But it continues to be used in some specialty applications such as guitar and audio sound effects and some types of sensors. It consists of a series of capacitance sections where a […]
What’s a logarithmic resistor ladder good for?
A logarithmic resistor ladder consists of a resistor string and switches designed to attenuate a signal. The state of the switches can be considered to represent a digital code proportional to the logarithm of the attenuation ratio. Logarithmic attenuation is useful when a large dynamic range is needed. Audio volume control and fading/balancing audio signals […]
