How To Make Automatic Light Lamps With LDR

by | Mar 14, 2022 | Physics, Science

Home » DIY » How To Make Automatic Light Lamps With LDR


Today, we will show you a stepwise tutorial on how to make automatic light lamps with LDR.

LDR stands for Light Dependent Resistor. It is the resistor that changes its resistance when light falls in it. It also acts as a light sensor and is widely used in light sensing circuits.


To make automatic light lamps with LDR, we need tools and materials, which are listed below.


  • Soldering iron


  • Small LDR (Light Dependent Resistor)
  • BC 547 transistor
  • 3v LED
  • 1k and 10k resistor
  • 3v battery

Steps To Make Automatic Light Lamps With LDR

To make an automatic light lamp with LDR, just follow these steps carefully;

 Step 1: Take a transistor and bend its leg (as shown in the picture).

Step 2: Add an LED bulb on one leg using a soldering iron.

Step 3: Now, connect a 1k resistor on the middle leg.

Step 4: Add a 10k resistor through the LED bulb and connect both resistors.

Step 5: Now, connect LDR with the 3rd leg and resistor (as shown in the picture).

Step 6: Now test with 3v battery, connect both battery wires in the circuit, and turn on the battery switch.

Step 7: When light doesn’t reach the LDR, the LED bulb glows.

Automatic Lights with LDR


This tutorial will help students understand the working concept of LDR & lamps and how they can be made by using the easily available material at home.

Things To Remember

  • Be careful while using soldering iron.
  • Be secure when connecting the wire.
  • Use the material available at home.



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