How to Regulate Voltage in Electronic Circuits or Reduce voltage dropping in power supplies.
By: Alok kumar
Generally the sole purpose of a power supply is to provide power to an electronic circuit so that we can operate that circuit within safe voltage and current tolerance/ range. For a given amount of power, there is an inverse relationship between voltage and current (ohm's law V=IR, where v is voltage across the circuit, I is current in the circuit and R is the equivalent resistance across the circuit). Whenever there is an increase in current there must be a voltage, and whenever current decreases,voltage must increase. This simple phenomenon unfortunately, has an adverse effect on power supply circuits.
When anyone connect a voltmeter to the output terminals of a power supply, the voltmeter itself draws current ( but an almost of insignificant amount ) so the meter reads very close to the voltage anyone should expect to obtain from the power supply.
However, if one connect a circuit which draws a significant amount of current from the power supply, then there will be a voltage drop occurs in perportion to the amount of current.
Depending on the nature of the circuit one is connecting to the power supply, this voltage drop
may or may not be a bad thing for most of circuit which is insensitive to voltage variation but some circuits which is designed for 12 VDC or some fixed value DC then the circuit may not function properly. In that case the power supply needs to workeven harder to make sure it delivers the desired
voltage to the circuit to function properly.
So power supply have to maintain that value and to maintain that steady voltage level regardless of the amount of current drawn from a power supply, the power supply need to incorporate a voltage regulator circuit. The voltage regulator circuitory usulaay monitors the current drawn by the load and according to that it increases or decreases the voltage accordingly to keep the voltage level fixed or constant.
So simply when a power supply incorporates a voltage regulator circuitory is called a regulated power supply.
Anyone can design their own voltage regulator circuit, but it is very easy to buy one of the many
available integrated circuit (IC) voltage regulators in the market to save the time. Generally voltage
regulator ICs are inexpensive and, with we only have to simply connect three pins, really very easy to incorporate into any circuit which requires a regulated power supply. In the market the most popular type of voltage regulator IC is the 78XX series, sometimes it is called as the LM78XX series too. These voltage regulators IC's is the combination of 17 transistors, three
Zener diodes, and a handful of resistors into one easy to use handy package with three pins. We also have to buy a heat sink (aluminium bar) which helps the IC to dissipate the excess power consumed by the regulator for compensation for the increases or decreases in current draw to keep the voltage at a constant level or fixed level.
