Sunday, November 9, 2014

Dark Sensor on a Breadboard (review)

                  Dark Sensor on a Breadboard

Here's a nice little Night light Circuit for you:


I use it with an Ultra High Brightness Blue LED (10mm), available from Radio Shack.
That produces enough light to navigate through a room at night, without turning on any other lights.

With a minor modification, it can be used with 4 AA NiMH batteries (4V to 5.6V), although the specifications call for 6V. It has been working very well for me. Other schematics for 6 volt and (only) one transistor variations are available from the web site.

In order to use the circuit with 4 AA batteries, just bump up the resistors to all be 1K Ohms.
The 4 AA NiMH batteries last about a few days, so I have found it useful to add a low voltage indicator.

Dark Sensor on a Breadboard from

Low Battery Indicator Using Two Transistors

A nice low battery indicator circuit is available here:

Conveniently, this circuit provides a low voltage circuit that works well with the above automatic night light, using 4 AA NiMH batteries.

It has an adjustable preset (roughly, a 50K potentiometer), which can be set for a variable number of batteries.

The web page also includes instructions for reversing the circuit to use it as a high battery indicator. The high battery indicator could be useful of you also charge the AA NiMH batteries.

Another one of my favorites from Mr. Swagatam Majumdar.


Low Battery Indicator Using Two Transistors from Homemafe Circuits Just For You


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