How to build Battery-powered Night Lamp

Ultra-low current drawing
1.5V battery supply

Circuit diagram

R1,R2 1M 1/4W Resistors
R3 47K 1/4W Resistor (optional: see Notes)
R4 Photo resistor (any type, optional: see Notes)
C1 100nF 63V Polyester Capacitor
C2 220µF 25V Electrolytic Capacitor
D1 LED Red 10mm. Ultra-bright (see Notes)
D2 1N5819 40V 1A Schottky-barrier Diode (see Notes)
IC1 7555 or TS555CN CMos Timer IC
B1 1.5V Battery (AA or AAA cell etc.)

Device purpose:
This circuit is usable as a Night Lamp when a wall mains socket is not available to plug-in an ever running small neon lamp device. In order to ensure minimum battery consumption, one 1.5V cell is used, and a simple voltage doubler drives a pulsating ultra-bright LED: current drawing is less than 500µA.
An optional Photo resistor switches-off the circuit in daylight or when room lamps illuminate, allowing further current economy.
This device will run for about 3 months continuously on an ordinary AA sized cell or for around 6 months on an alkaline type cell but, adding the Photo resistor circuitry, running time will be doubled or, very likely, triplicated.

Circuit operation:
IC1 generates a square wave at about 4Hz frequency. C2 & D2 form a voltage doubler, necessary to raise the battery voltage to a peak value able to drive the LED.

IC1 must be a CMos type: only these devices can safely operate at 1.5V supply or less.
If you are not needing Photo resistor operation, omit R3 & R4 and connect pin 4 of IC1 to positive supply.
Ordinary LEDs can be used, but light intensity will be poor.
An ordinary 1N4148 type diode can be used instead of the 1N5819 Schottky-barrier type diode, but LED intensity will be reduced due to the higher voltage drop.
Any Schottky-barrier type diode can be used in place of the 1N5819.

Author: RED Free Circuit Designs

Similar diagrams

We are not responsible for any injuries or damage caused by information from this website! Working with electricity is dangerous for your life, especially diagrams related to high voltage! We do not guarantee success in building devices using our diagrams! They are not tested by us. For questions about diagrams use author info below diagram or our contact page. Thank you!