In order to obtain a sound signal of high power (10-20W) simple sound generator, no need for complex CC amplifiers. Generator popular chip CREW enabled by well-known "classic" scheme and in the description does not need. The output frequency is approximately 1000 Hz. It can be calculated by approximate formula:

A sound generator as siren

where the value of F is in kHz. R1, R2 - kiloomah, and C2 - microfarad. Frequency can be significantly adjusted by changing the values of C2 and R2.

Output circuit (the output 3DA1) does not provide significant power, so a field-effect transistor VT1 implemented USC of course, you Can use ordinary bipolar transistor, for example. KTM connected to a common emitter the wire, collector - to BA1, and base-3DA1 through a current limiting resistor resistance 470...820 Ohms. However, in this case a field effect transistor preferable, as in the open position by moving the source-drain has less resistance, and therefore, the field-effect transistor will be greater efficiency.

Instead of a field-effect transistor BUZ11 can include similar electrical the characteristics of field-effect transistors IRF521, IRF540, setting them on heat sinks (when the power dynamic heads more than 5 watts) All fixed resistors - MLT-0,25. MF-25. Dynamic head of BA1 - any designed for a capacity of 10. ..20 W coil resistance 4 Ohms. At higher resistance heads, for example, 8 Ohms, power will be reduced proportionally. Oxide capacitor C1 K50-29 or similar, non-polar capacitors C2, C3 - km-6. K10-17, KT-23, KWS or similar. The capacitor C3 is connected to pin 5 DA1 to protect against interference from the scheme can be deleted.

Power source required stable. with an output voltage of 15 V. 9... The higher the voltage, the higher the output power of the amplifier. When using powerful dynamics (10-20W) from source requires an output current of at least 10 7... A.

Such a device can be used as alarm sound remote protected sites. The dynamic head is directly BA1 on the street, and the signal can be heard very far.

Author: A. Kashkarov

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