GENERATOR Who has not experienced the beneficial effects of the measuring noise of the rain forests, the sea… the sound relaxes and soothes. That is why the simulator of the surf, which we offer to readers, is used as a stimulant of sleep in insomnia. Generator “of the sea” is easy to manufacture and configure, does not contain scarce radio parts and accessible even for novice radio Amateurs. Here’s how it works.
As a source of “white” noise is used sverhekonomichny cascade transistor V1 (Fig. 1). With it through low pass filter R5, C10 signal “white” noise is supplied to the amplifier stage V2. The power transistor V2 is supplied from the capacitor C12, which is periodically charged via the electronic key, assembled on the transistor V3. The electronic key controls the multivibrator V4, V5. And since the voltage at the transistor V2 varies periodically, the modulation of the white noise amplitude. The result is a sound resembling the noise of the surf.
Fig. 1. Schematic diagram of the simulator.
Fig. 1. Schematic diagram of the simulator.
About modulated white noise from the manifold V2 is supplied to the two-stage low-frequency amplifier V6 — V8.
Simulator of the surf is mounted on a printed circuit Board made of foil fiberglass with a thickness of 1-2 mm (Fig. 2). The device used fixed resistors MLT-0,125, the tuning SDR-1B, K16 — variable resistor SPZ-3V. Electrolytic condensers — K50-6, the capacitor C17 — MBM, the rest KM or K10-7. Choke L1 D 0,1 is the inductance of 30 to 100 µh. Coil L2 — frameless, Ø 4 mm, includes 24 turns of wire PEL of 0.3 with a tap from the middle. КТ315В transistor can be replaced by KT315 or ГТ311 with any alphabetic index, the other transistors is any structure p-n-p.
Fig. 2. Wiring diagram of the device.
Fig. 2. Device wiring diagram.
Adjust the unit as follows. Resistor R8 otpaivat from the capacitor C12 and is connected to the “minus” of power supply. Choose the resistance R1 until the loudspeaker characteristic sverhsekretnoj noise. Thereafter, the resistor R8 is set on a former place. Changing the resistance R14, select the frequency of the “marine waves”. From the values of R9 depends on the rise time of a “wave”, and R11 from the time of its decline.
For a more natural imitation of the sound of the surf device it is recommended to connect to external ULF increased power.
A. KOZYAVIN, Voronezh

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