There are two groups of classic circuits: those which have served us well in the past, but have been superseded by better designs, and those which are still in use, perhaps with updated components. In ...

This home smoke detector circuit warns the user against fire accidents. It relies on the smoke that is produced in the event of a fire and passes between a bulb and an LDR, the amount of light falling ...

Fig 1. Fires follow a progression from start to full involvement, with both temperature and smoke content rising rapidly once full combustion is underway. Fig 2. Traditional optical smoke detectors ...