LDR Control Circuit | Electronic Project Circuits

Posts Tagged ‘LDR control circuit’

Electronic mailbox front door with ic 555

Living in the current rush to waste time to even have little value. Electronic circuits, so one is important in everyday life.Which saves time and convenience.
For example, this circuit. It gives us no time to wait to check voice mailbox.We see the LED is just enough.
Operation of the circuit. While no letter LDR will receive light from the lamp. The LDR resistance is very low. Resulting in IC does not work.
There is no output from the 3 pin. It make the current flows through R2, LED2 into three legs of IC1.The light LED2.But when a letter in the mail box to shield the light from the lamp. The LDR is not light. LDR will be much resistance.Voltage drop across the LDR is high enough to make IC1 work.
IC1 to produce frequencies from 3 pin. The light LED1.

Be the first to comment - What do you think? Posted by admin - September 8, 2010 at 5:56 pm

Categories: Detector, Electronic Control Tags: electronic mailbox alert, LDR control circuit, led display warn

Active light control by LDR and BC337

This is automatic light circuit when be become dark. It by use LED Lamp, be a place gives the light and this circuit has small-sized use volt supply 3V only.

The work of the circuit be when there is the light affects LDR1 will valuable the resistance at LDR1. It be down make Q1 work be born volt at fall straddle a pin C of Q1 compare with Ground be valuable a little more voltage bias to make Q2 work. By have D1 serial with a pin B of Q2 make volt at pin C of Q1 compare with ground must use volt about 1.4V arrive at make Q2 work. But when LDR1 no the light will make to is valuable the resistance more and more until make to have no current flow get along well with B of Q1 make Q1 do not work. Then have current flow through R1,D1 get along well with pin B of Q2 work cause LED1 stick bright. The part , VR1 , parallel connection with , LDR1 , as a result , for take keep fine the rapidity in taking light of LDR1

Be the first to comment - What do you think? Posted by admin - May 1, 2010 at 11:36 pm

Categories: Electronic Control, Lighting Tags: Automatic light switch, LDR control circuit, light dark detector circuit

Simple light sensitivity Metronome using 2N3904

This is Simple light sensitivity Metronome circuit. It use the transistor 2N3904 numbers and 2N3906 make to are origin frequency circuit. By the frequency in the sound from a loudspeaker will increase and is down. When lead light flasher come to near LDR within a darkroom. By resistance value of LDR be down when receive the light. Which will enhance the frequency of origin frequency sound circuit. By frequency change will continuously is like the wood keeps strokes the music there. The detail is other , see in the circuit.