This is a very simple touch sensor switch that is build with the 555 timer IC. You just need to touch the metal plate and the relay gets energised and is kept in this state for about 100 seconds, then ...

The 555 timer IC has been around now for quite some time and the list of potential uses for this device appears to be endless. This article contains a few examples of circuits that you might ...

The 555 timer IC is an integrated circuit (chip) which is used in a variety of timer, delay, pulse generation, and oscillator applications. 555 Signals and Pinout (8 pin DIP) Figure below shows the ...