ELECTRONIC BELL FOR BICYCLE | MODEL CONSTRUCTION

Conventional Bicycle bell has a number of disadvantages: inconvenient to work with, rattles while driving even on a flat road makes a sharp, unpleasant sound.

From these shortcomings are free electronic call. In addition, it is easy to change the volume and tone of sound. The device operates as follows. With the closure of the button S1 (Fig. 1) asymmetrical multivibrator transistors V1, V2 starts to generate oscillations of audio frequency. They come in single-stage amplifier V3, V4, assembled on a composite transistor. At the same time from the battery G1 charging the capacitor C2, which after the button is released continues to fuel the e-call. The tone of its sound increases and the amplitude decreases, resembling a siren. Resistor R3 limits current consumption and is made of cut spiral for electric.

You can use capacitors and resistors of all types. Transistors V1, V3, and V4 series МП39 — МП42 and V2 — series MP35 — MP38 gain current of 20-60.

The load you can use any small-sized dynamic head of the resistance of the voice coil is not more than 10 Ohms, for example, DGD-6.

Fig. 1. Schematic diagram of the electronic call.

Fig. 2. Wiring diagram.

Power — battery “Krona” or two series-connected battery 3336L.

Establishing device is reduced to selection of the value of the resistor R1 to obtain the desired tone sound. Electronic bell (Fig. 2) is mounted in a small case. It is attached to the steering rod, and a button under the brake handle.

G. MARKAROV, A. PLOTNIKOV

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