Circuits & Schematics - 9

The need for conditioning low-level ac signals in the presence of both common-mode noise and differential dc voltage prevails in many applications. In such situations, ac-coupling to instrumentation and difference amplifiers is mandatory to extract ...

Many portable appliances and other products that must operate from a single cell are restricted to working at very low voltages. It is thus difficult to drive white LEDs that typically have a forward voltage of 3 to 5 V. The ability to flash the ...

The control of electronic potentiometers in most today's applications comes from controller-generated signals. However, a significant number of applications exist that require adjustments using manual, front-panel controls. The circuit in ...

This expandable LED display for a microcontroller in Figure 1 has a simple interface with only 6 data/control wires and can be easily accommodated to a DIY design. The display has static indication. Figure 1. The expandable LED display for a ...

Long ago in a galaxy far away (actually, the same galaxy but the Milky Way is moving so it must logically be far away from where it was way back then), I sketched up a simple circuit for a DC coupled amplifier that I thought (in my youthful ...

Sensors that detect and track small metallic objects are handy gadgets, whether used to route workpieces on an assembly line or comb a beach for “treasures” lost in the sand. A typical sensor design consists of an inductor integrated ...

If someone in your family has the habit of not completely closing a drawer or perhaps the food freezer’s door you’ll appreciate this design. It senses an ajar door and, if the situation isn’t corrected within 20 sec, sounds a ...

LVDTs (linear variable differential transformers) are electromechanical measuring devices that convert the position of a magnetic core into electrical signals. You generate these signals via excitation on the primary side. The results on the ...

A previous Design Idea describes a programmable current source that used a three-terminal LM317 adjustable regulator (Reference 1). Although that circuit lets you program the output current, the load current flowed through the BCD ...

Almost all precision voltage-to-frequency converters (V-F) utilize charge pump based feedback for stability. These schemes rely on a capacitor for stability. A great deal of effort towards this approach has resulted in high performance V-F ...