A previous Design Idea describes a circuit that uses an astable multivibrator to drive an LED (Reference 1). The circuit in Figure 1 uses a simpler alternative approach. The circuit uses a 2N3904 NPN ...

Matching a sensor interface with a programmable logic converter or controller hardware that can accept only one type of input—npn or pnp—can be difficult. The last-stage modification circuit described ...

In multiple-output power supplies in which a single supply powers circuitry of vastly different current draws, two perplexing steps are sensing the current that each output draws and deactivating the ...