Agreeable, relaxing effect, helping to fall asleep
Small portable unit, 3V battery powered
Sound effects generators trying to imitate rain sound or sea surf are well known to hobbyists from many years: their purpose is to induce relaxation and sleep or to help in concentration and study.
The sound generated is restrained to a background level and these devices are frequently kept on the night table.
Common designs use invariably Zener diodes or reverse-biased transistors base-emitter junctions as white noise generators. The main snag of these circuits is that a supply of at least 12V is required, therefore a big battery pack or (more commonly) mains supply is used as power source.
The aim of this project was to design a small, portable unit, powered by a 3V battery and capable of shutting-down after a preset delay, in order to save power.
Parts:
[...]
C1,C4,C7______100µF 25V Electrolytic Capacitors
C2,C3,C6______100nF 63V Polyester or Ceramic Capacitors
C8,C10________100nF 63V Polyester or Ceramic Capacitors
C5_____________47µF 25V Electrolytic Capacitor
C9_____________10µF 63V Electrolytic Capacitor
D1___________1N4148 75V 150mA Diode
Q1___________2N3819 General-purpose N-Channel FET
Q2____________BC337 45V 800mA NPN Transistor
Q3____________BC327 45V 800mA PNP Transistor
Q4,Q5_________BC547 45V 100mA NPN Transistors
IC1___________TL062 Low current BIFET Dual Op-Amp
IC2____________4060 14 stage ripple counter and oscillator IC (See Notes)
Please read more at the original source: http://www.redcircuits.com//Page75.htm
Thank you.
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This entry was posted on Sunday, February 3rd, 2008 at 2:04 pm and is filed under Audio - Alarm.
