Discrete Sliding Tone (Frequency Ramp) Doorbell

This doorbell circuit produces a low tone that will slide up to higher frequency. The equivalent total resistance connected between the base of Q1 and ground (Rbg) , and coupling capacitor¬† C1¬† determines the AF oscillator’s frequency. The resistance (Rbg) is equal to (R2+R1)R3.¬† Here is the schematic diagram of the circuit: The R2 is used to set the initial […]

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