This circuit is suggested by National Semiconductor and is based on the LM3900, a quadruple transconductance operational amplifier. The operating frequency of the circuit is that of the transducer resonance and excellent audio power is achieved with this type of element. The 15 V supply comes from a non-symmetrical source. The other operational ones of the LM3900 integrated circuit can be used for other applications or to generate signals for other transducers.
