Brad Albing

Common designs for touch switches detect a decrease in resistance when a user's fingertip either connects a contact to the circuit's common ground or supplies an injection of 60-Hz ac voltage, resulting from immersion in the electrostatic field that nearby power lines...

Many suitable circuits exist for driving LEDs in constant-current mode and from low-voltage sources. For example, references 1, and 2 show circuits that use switched-mode-regulator ICs and low-voltage sources to supply LED current. To produce a constant-current output using the...