Simple Dark Activated Switch

You all know FREE CIRCUIT DIAGRAMS 4U always try to give simple and useful circuit diagrams.Today we are going to give you a Simple dark activated circuit diagram.When the dark comes this circuit will activated.This circuit is operated with 12v power.Most of time these types of circuits are used to design robot hands etc.And also you can make a counter of people.For that you can use a lazer pointer and aim it to the LDR.When a person is passing.Lazer beam will cut due to that the circuit will activate.you can use this circuit for various things so try this...

Note:
        # Build this circuit on a PCB 
        # Don't supply over 12V

Magnatic Power On Off Switch

This is very useful circuit Diagram already Free Circuit Diagrams 4U has given you many useful circuit diagrams.Today We are going to give you a magnetic power on off switch basically this circuit diagram is with robots.By using a magnet you can on and off this circuit.this circuit can be operated with 9V power supply.And also when you make burglar alarms you can use this circuit diagram.

Note:
         # Build this circuit on a PCB
         # Try to make different things by using this circuit diagram

Simple Water Level Detector

This is so useful circuit diagram because this circuit helps us to detect water.When the water come and touch the sensors it will make a sound.Here I have used common transistor bc109. Actually you can modify this circuit.. By using a relay you can switch on or off your water motor I will tell you them in my next post.

Siren for Factories ( 2)

This is powerful siren circuit diagram.You can get lots of supports from this circuit because you can use this circuit for your alarm circuit then you will be able to get maximum results.

Siren for Factories (6W)

This is a siren circuit diagram But this circuit is little bit different.Because this circuit can generate up to 6W power here I have used famous IC 4011