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 […]
FAQ: Piezoelectric motors, Part 1: actuators
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. When we think “motor”, we usually think of rotating motion or perhaps a special “linear motor” which is a rotary motor which has been rolled out flat. To […]
Optocouplers, Part 2: Parameters and applications
Part 1 of this FAQ explored the basics of the optocoupler. This part looks at key parameters and some application examples. Q: What are the primary factors used when assessing an optocoupler? A: While there are many important factors, there are several which are noteworthy: isolation, current-transfer ratio (CTR), linearity (for analog use), and speed. […]
What are diodes? A quick refresher
A diode is a passive component made with semiconductor materials (a chip) that conducts current flowing in one direction but does not conduct current flowing in the opposite direction. The symbol for a diode (to the right in Figure 1) looks something like an arrow pointing in the direction of the forward current. Current flows […]
Load switches, Part 2: IC implementations and benefits
Part 1 of this FAQ looked at the need for the load-switch function for a circuit’s DC rails, the basic implementation using a MOSEFT and driver, and the limitations of this approach. Part 2 looks at what are referred to as load switches, which in this context means ICs designed to implement the load-switch function, […]
Load switches, Part 1: Basic role and principle
Load switches are used to enable/disable power to selected ICs or circuit subsections. Although they don’t get much attention, they are useful for both saving power as well as management of multiple power rails. This FAQ will discuss their function, basic design, advanced IC implementations, and additional benefits of IC load switches. Q: What is […]
Voice-coil actuators, Part 2: Application issues
Part 1 looked at the basic of the VCA. Part 2 looks at operation in more detail along with applications, as well as a comparison to the solenoid. Q: What equation governs the behavior of a VCA? A: As with most magnetic-coil devices, it’s the Lorentz force equation. This shows that the force generated is […]
Voice-coil actuators, Part 1: Principle basics
When designers need a modest amount of motion and power, they naturally think of a motor. That makes sense since there’s often a brushed, brushless, or stepper motor that can meet the objectives, sometimes with some necessary add-on gearing. Or they may think of a solenoid for impact-type linear motion. This FAQ looks at another […]
Wireless charging, Part 2: Implementation
Part 1 of this FAQ looked at the overall context of wireless charging of personal devices. This part looks in more detail at the approaches to wireless charging and the implementation specifics. Q: What approaches are available for wireless charging? A: There are three basic topologies: single-coil inductive, multi-coil inductive, and resonant. Q: What are […]
Wireless charging, Part 1: Context
Wireless charging of devices is a hot and growing area. This FAQ explores the rationale and options for implementing this form of energy transfer, storage, and charging. Q: What is wireless charging? A: It consists of two functions which are closely linked. The first is the transmission of electricals power wirelessly from a transmitting source […]
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