FREE CIRCUIT DIAGRAMS 4U: Battery Powered Night Lamp

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Electronic Circuit,Schematic Diagram,Circuit Diagrams

electronic circuit, circuit diagram, circuit schematic, schematic diagram, electronic diagram, audio, amplifier, power supply, guitar effect, current loop, current limiter, video, receiver, transmitter, transceiver, transistor, radio frequency, rf, active filters, digital, analog circuit, pwm, micro controller Free download

Saturday, September 05, 2009

Battery Powered Night Lamp

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 simple voltage doublers drives a pulsating ultra-bright LED: current drawing is less than 500µA. An optional Photo resistor will switch-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, triplicates. IC1 generates a square wave at about 4 Hz frequencies. C2 & D2 form voltage doublers, necessary to raise the battery voltage to a peak value able to drive the LED.

Parts:

R1 = 1M
R2 = 1M
R3 = 47K
R4 = LDR
C1 = 100nF-63V
C2 = 220uF-25V
D1 = Ultra Bright 10mm LED
D2 = 1N5819 B1 = 1.5V Battery or AA Cell
IC1 = 7555 CMos Timer IC

Notes:

* IC1 must be a CMos type: only these devices can safely operate at 1.5V supply or less. * If you do not need 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, e.g. the BAT46, rated @ 100V 150mA.