A capacitance sensor includes flexible interdigitated electrodes and an uncomplicated, compact control circuit including a frequency meter, a resistance capacitance oscillator, a display, and a microcontroller to manage these components. In an exemplary method of use of the capacitance sensor to monitor known parameters of a fluid, the flexible electrodes may be inserted into a circular tubular conduit containing the fluid. As fluid flows past the electrodes, any discrepancies from the known parameters may be detected and signaled immediately.

A capacitance sensor includes flexible interdigitated electrodes and an uncomplicated, compact control circuit including a frequency meter, a resistance capacitance oscillator, a display, and a microcontroller to manage these components. In an exemplary method of use of the capacitance sensor to monitor known parameters of a fluid, the flexible electrodes may be inserted into a circular tubular conduit containing the fluid. As fluid flows past the electrodes, any discrepancies from the known parameters may be detected and signaled immediately.

A power inverter, such as a synchronous buck power inverter, that is configured with a high frequency switching control having a (PWM) controller and sensing circuit. Controller provides a low frequency oscillating wave to effect switching control on a synchronous-buck circuit portion that includes a plurality of switches to invert every half cycle of the frequency provided by controller. The inverting process thus creates a positive and negative transition of the oscillating wave signal. A low frequency switching stage includes a further plurality of switches configured to operate as zero voltage switching (ZVS) and zero current switching (ZCS) drives Charge on an output capacitor is discharged to zero on every zero crossing of low frequency switching stage and advantageously discharges energy every half cycle. During this discharge of energy, the zero crossing distortion in the low frequency sine wave is greatly reduced.

An oscillator circuit that includes a Wien bridge oscillator circuit, a full-wave rectifier circuit, coupled to an output of the Wien bridge oscillator circuit, an integrator circuit, coupled to an output of the full-wave rectifier circuit, and a multiplier circuit. The multiplier circuit may include a first input coupled to the output of the Wien bridge oscillator circuit, and a second input, coupled to an output of the integrator, wherein the multiple signals are configured to provide dynamic gain control to the Wien bridge oscillator circuit.

A power inverter, such as a synchronous buck power inverter, that is configured with a high frequency switching control having a (PWM) controller and sensing circuit. Controller provides a low frequency oscillating wave to effect switching control on a synchronous-buck circuit portion that includes a plurality of switches to invert every half cycle of the frequency provided by controller. The inverting process thus creates a positive and negative transition of the oscillating wave signal. A low frequency switching stage includes a further plurality of switches configured to operate as zero voltage switching (ZVS) and zero current switching (ZCS) drives Charge on an output capacitor is discharged to zero on every zero crossing of low frequency switching stage and advantageously discharges energy every half cycle. During this discharge of energy, the zero crossing distortion in the low frequency sine wave is greatly reduced.

An oscillator circuit that includes a Wien bridge oscillator circuit, a full-wave rectifier circuit, coupled to an output of the Wien bridge oscillator circuit, an integrator circuit, coupled to an output of the full-wave rectifier circuit, and a multiplier circuit. The multiplier circuit may include a first input coupled to the output of the Wien bridge oscillator circuit, and a second input, coupled to an output of the integrator, wherein the multiple signals are configured to provide dynamic gain control to the Wien bridge oscillator circuit.