With the source taken care of [Glitch] uses an optoisolator for both protection and level conversion. After working the bugs out of the design he was able to control the relay using 3.3V, 5V, or 12V.

The circuit uses a 78L05 linear regulator to decrease the power-supply voltage to 5V. The 1N4007 between the 24V dc and the 5V LM7805 regulator protects the circuit from possible power-supply wire ...

IC-Haus introduced the iC-HD2, iC-HD7 and iC-HE line drivers for 5 V and 24 V industrial encoder/sensor applications. The output drivers are designed for cable impedances in the range of 30 to 140 ...

I was pondering possible interfaces between a microcontroller and a 12 or 24V 5015 blower fan. The challenge is that the MCU can only drive 3.3 or 5V, while the blower needs needs a voltage as low as ...

The 24V output voltage can be programmed using the 800mV 1% reference or one of the preset voltages. This circuit uses the 5V preset option along with feedback resistors to program the output voltage.

Diodes, one-way current conductors, are used for voltage regulation, AC/DC conversion, and circuit protection. Forward-biased at 0.6V, conduct current, reverse bias blocks it.