In order to obtain a sound signal of high power (10 – 20W) from the simple Assembly of a sound generator, does not require complex amplifiers WOOFER.
The generator on the popular chip KP1006BU1 (DA1) is enabled by almost classical scheme and in the description is not needed. The output frequency is approximately 1000 Hz. It can be considerably corrected by changing the values of the elements C2 and R2. The output frequency in this circuit is calculated by the formula:
F(kHz) = 1,44/(R1 +2xR2)xC2, where the resistance of the resistors R1, R2 in ohms, and the capacitance of the capacitor C1 is in microfarads.
The IC output (pin 3 DA1) cannot provide significant power, so the FET VT1 is implemented power amplifier. You can, of course, be applied to ordinary bipolar transistor, such as the type КТ819БМ (by connecting its emitter to ground, collector to BA 1, base to terminal 3 DA1 through a current limiting resistor 470 and 820 Ohms). However, in this case a field-effect transistor as a power amplifier is better, because in the open state, the transition “drain — source” has less resistance, which means that FET will be negligible power loss and accordingly greater efficiency.