No abstract

Analog Computers can realize most of mathematical equations; these equations can be solved using difference, adder, logarithmic, anti-logarithmic, integrator, and differentiator amplifiers. The logarithmic and anti-logarithmic amplifiers are the main components of the analog computers, whereas, they can convert the multiplication and division operations to addition and subtraction ones, and they can convert the exponential functions to multiplication relationships. These amplifiers depend on the non-linearity of the relation between forward current and applied voltage of the diode. All of previous types of wattmeters, measure the consumed power of a specific load or resistor by multiplying the difference voltage of that load by the current passes through it (i.e. P=V.I). In this paper, a proposed accurate wattmeter circuit has been designed and implemented using logarithmic, anti-logarithmic, non-inverting, and difference amplifiers. The proposed circuit has been utilized for measuring the consumed power of a resistor that have any resistance value. It differs from previous conventional (analog, and digital) wattmeters due to its calculation of the consumed power for a given resistor by multiplying the voltage difference (V) across that resistor by itself once time, then the resultant value is divided by the resistance (R) value of that resistor (i.e. P=V 2 /R).

The main problem of traditional LC ( L represents the inductance, and C represents the Capacitance) Voltage Controlled Oscillators VCOs, is the nonlinearity relation between the tuning control voltage and output resonance frequency, which is caused by two following reasons: the first one is the inverse and non-linear relation between the tuning control voltage and produced capacitance of the used varactor diode in the VCO circuit, and the second is the inverse and non-linear relation between the capacitance value of the used varactor diode and the output resonance frequency. In this paper, a proposed circuit has been designed and implemented to solve this problem and realize a direct-linear relation between the tuning control voltage and output resonance frequency for the LC Voltage Controlled Oscillator that utilize the varactor diode as a voltage controlled capacitance. The proposed circuit has been realized using Logarithmic, Inverting, Ant-Logarithmic, and Difference Amplifiers, which they are characterized by their simplicity and low cost. The theoretical and practical results of testing the proposed circuit had been presented using MATLAB software package. The proposed work has been practically tested by 21 measurement points, whereas, it has exhibited stimulant results that supports the successfulness of its design and performance.