Schematics and components

Post date: Aug 10, 2016 4:29:19 AM

Schematic:

Description:

The voltage divider R5/LDR is saturating the base of a BC547 NPN transistor via R4.

According to the LDR datasheet when light condition is dark the resistance of the LDR is 500k Ohm.

R5=1.5 M Ohm and R4 1k Ohm should be enought to reach the 0.7V of the BC saturation voltage.

I plan to use 2 LED cut off from 12V LED strip, the resistor R3 is just for the schematic because those resistors are already inside the LED strip.

Components:

• NA02-2S12 12Vdc

• LDR VT90N2

• Resistor 1M Ohm

• Resistor 1K Ohm

• Transistor BC547B

• 2 Led from Strip LED