TRS. LDR REMOTE SWITCH

6TP06

2B-TRANSISTER REMOTE LDR SWITCH

PROJECT SPECIALITIES

The specialty of this project is that you can put ON any equipment sitting far away with the help of this project. This project act as a switch and can control equipment like fan, motor etc. This project will prove a boon for a technician who has to do wiring job for switching.

TECHNICAL DESCRIPTION AND WORKING

This project has been developed and tested O.K. in our TV Engineers Technical Lab.  The components and PCB used in the projects published in our books are available for sale at resonable price.

With the help of this project there is no need for wiring because this project is based on a cordless system.

The circuit is constructed with the help of transistors. In this project 3 Nos BC548C and 1 Nos AC128 have been used. When light falls on the LDR then at that time a negative going pulse flows in the base of transister Q1. It becomes positive at the collector of this transister. Due to the presence of diode D1 and D2 it reaches in the base of Q2 and Q3. Q2 and Q3 make an bi-stable multivibrater. Due to positive going pulse these transistors comes in the cut-off stage. It means collector voltage of Q2 and Q3 becomes equal to the supply voltage. Q4 transister is connected at the output of the circuit and act as a switch. Q4 closes when Q3 is in saturation. This circuit operates on the supply of 9 Volt DC. Diode D3 and capacitor C7 are connected with the relay for it protection. These do not allow the interference signal to the other part of the circuit from the relay.

This circuit is quit different from the other frequency controlled circuit because this circuit depends upon the light falling on the LDR. Mostly frequency controlled Circuit { Cord-less } malfunction like sparking in the electrical plug. Electrical sparking is created due to automobiles. Frequency controlled circuit mostly create problems where there is no difficulty with the LDR switch.

PRECAUTIONS WHILE ASSEMBLING THE PROJECT:-

* Never give DC voltage more than rated value on LDR. It may spoil it.

* While connecting diode take care of it polarity.

* Never put ON the project if there is a short in the transister.

* Take special precaution while assembling transister about its base, emitter and collector.

* Take special precaution about polarity of diode while assembling it on the PCB.

PART LIST:-

PCB [CODE 6TP06]

Semi-Conductor

BC548=3, BEL128=1 LDR=1

LED=1, IN4007=4

Resistance

100E=1, 10K=1, 39K=1, 10K=2, 1K=2, 1K2=2, 680E=2, 6K8=2, 5E=1, Preset 10K=1

Capacitor

10mfd/25V=2, 22Omfd/25V=2, 33mfd/25V=1, 470mfd/16V=1, 0.1mfd=1,0.047pf=1

RELAY 12V =1

Misc.:-

Cabinet =1

One Pensil Torch=1