How Convert Voltage to Frequency

Written by: 110220volts Published by: 110220volts Copyright holder: 110220volts on 07/11/2015

Voltage can be defined as the difference in electric potential energy between two points per unit electric charge. The voltage between two points is actually equal to the work done per unit of charge against a static electric field in order to move the charge between two points. Voltage is measured in volts (a joule per coulomb).

Frequency in simple words can be defined as the number of cycles or completed alternations per unit time of a wave or oscillation. Unit of frequency is Hartz.

Voltage to frequency converter is simply a electronic conversion mechanism that converts voltage into frequency, or we can define voltage to frequency converter as s an electronic device that converts alternating current (AC) of one frequency to alternating current of another frequency. There are different types of converters which convert voltage to frequency depending on the ratings current, voltage and then output value regarding frequency. VFC are used in different applications

In certain applications the device may also change the voltage but if it does change the voltage that is related to its key purpose depending upon the working of application. Traditionally, these devices were electromechanical machines called a motor generators set which were used in the industries for performing various tasks. Also including the devices with mercury arc rectifiers or vacuum tubes were in use in past. But With the invention of solid state electronics, it has become possible to build completely electronic frequency changers or we can call as the frequency converters based on the electronics circuits. These devices that involve in the frequency conversion based on electronic circuitry are usually consisting of a rectifier stage that produces the direct current which can be then inverted to produce AC Alternating current of the desired frequency. The inverter may use thyristors, IGCTs or IGBTs. (these are minor electronic devices).

Frequency converter may also refer to a much lower powered circuit that converts radio frequency signals at one frequency to another frequency, especially in a super heterodyne receiver. This kind of circuit usually consists of a local oscillator and frequency mixer (analog multiplier) that generates sum and difference of frequencies from the input and local oscillator, of which one (the Intermediate frequency) will be required for further amplification, while the others are filtered out. The same result was achieved historically by the pentagram converter or a Triode and Hexode in a single tube, but can be implemented in transistor radios economically by a single transistor functioning as a self-oscillating mixer.

As we have discussed above that these kind of converter circuits can be made using various electronic components but now here we will see a frequency converter using a 555 timer as an Example.

Voltage to frequency converter circuit diagram using 555 timer:

By Using a 555 timer in the circuit and some other electronic components we can make a small voltage converter that provides a negative voltage of 12 V at a rate of a few milliamps. 555 circuits is connected as astable frequency of 125 kHz. Network C1-C5-D2-D3 (C capacitor and D diodes) form a cascade circuit which provides a negative DC voltage. Since in this type of scheme we will not use either a transformer or inductor, Although converter efficiency is not very high just up to 16% at a current of 20 mA output.