Circuits & Schematics - 9

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 ...

Whenever I find myself harboring a constantly nagging thought, I know I will eventually have to get busy and find a way to put it to rest. When I read EDN’s Design Ideas, I look for the range of frequencies over which the circuit will ...

Low-frequency filters, particularly at audio frequencies, usually take the form of active filters. These filters eliminate expensive inductors with windings of many turns. Both analog and digital active filters are most compatible with large-scale ...