A simple VCO using two inverters in a ring configuration is shown here. A VCO is a circuit in which the frequency depends on the voltage applied to the input. It can be used in applications, such as musical instruments and sirens. The central frequency depends on R1 and C1. This frequency changes based on the voltage applied to the control input. The Iimits of this voltage depend on the application, but the circuit can be used as a FM generator in applications where the generated frequency band is not very wide. For a wider band, VCOs prefer the 4046. With the values for R and C as shown in the diagram the circuit wiII oscillate in the audio band.
Voltage Controlled Oscillator (VCO)
