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LDR

Mattblack

May 7, 2015
4
Joined
May 7, 2015
Messages
4
hi,

I have bought some outdoor LED lights, they are powered by 2 x AA batteries, and it has an on off switch.

How could I add an LDR to the batteries so that the circuit is made when it gets dark?

What size resistor would I need and what type of transistor?

Apologies if it is a noob question!
 

Gryd3

Jun 25, 2014
4,098
Joined
Jun 25, 2014
Messages
4,098
hi,

I have bought some outdoor LED lights, they are powered by 2 x AA batteries, and it has an on off switch.

How could I add an LDR to the batteries so that the circuit is made when it gets dark?

What size resistor would I need and what type of transistor?

Apologies if it is a noob question!
How long do the batteries last?
Have you tried to find any example circuits for what you want?

The light detecting circuit will draw additional power.
 

Kiwi

Jan 28, 2013
471
Joined
Jan 28, 2013
Messages
471
Do your ones require you to switch them on at night and off in the morning?

The only outdoor LED lights I have seen are either;
1- Solar cell on top charges the internal battery during the day and the battery powers the LED at night,
2- Connected to an external mains transformer.
 
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