The circuit below shows a simple application of ldr operated switch. This circuit senses the ambience light and depending on the presence/absense of sufficient ambience light, it turnes the bulb ...

This musical light alarm circuit is very simple, uses only 7 components, a LDR and a 3.6 V battery or 3 x 1.2 volts rechargeable batteries. The well-known UM66 is used as the sound generator and will ...