Various tone generator circuit produces three different type of sound according to input three different logic levels (i.e. 0&1, 1&0 and 1&1).

 

Circuit description of One Tone Generator

         This circuit is designed around digital IC 7400 which is NAND gate. The working of the circuit is like the working principle of oscillator circuit, where frequency depends
upon capacitors C1 and C2. The duty cycle of this circuit is 50%. The output is given to power amplifier circuit which further drive loudspeaker or head phone. For low frequency value of capacitor C1 and C2 must be high and vice-versa.