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 ...
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 ...
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 ...
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 ...
Rail-to-rail input and output (RRIO) op amps, both FET and BJT, have been around for a long time, but the possibilities they provide for versatile waveshape generation with simple circuits can still surprise. Figure 1 is an example, outputting a ...
You can use a photoelectric FET as a variable resistor or a potentiometer in combination with a fixed resistor. The H11F3M photoelectric FET has an isolation voltage of 7.5 kV, enabling you to safely control high-voltage circuit parameters. The ...
Magnetic field strength verifier A simple way of producing a large magnetic field strength is to use a solenoid. The field strength and inductance can be calculated accurately from the physical dimensions and the current. The measured value of the ...
This project will explain how to develop a system to measure magnetic field emissions at frequencies up to 150 kHz from high-current power cables without cutting or disturbing the cable. Magnetic fields are present almost everywhere. However, ...
Powering portable telemetry systems for long-term monitoring presents interesting design challenges. Batteries are unsuitable for certain critical applications, and, in these circumstances, designers typically use wireless inductive links to ...