Checking the parameters like nominal value, tolerance, power rating, voltage drop, current through it, power dissipation by it and other properties, if required.Selection of a resistor through a quick circuit analysis.The most common process of selecting a resistor for a given application involves the following steps:

Some resistors are colour coded to indicate the values or ratings while some resistors have the values printed with numbers or letters on the bodies.ĭifferent types of fixed resistors commonly used in the circuits are shown in Fig.

The values in the range are chosen such that they follow an exponential curve, and when you replace your calculated value with one from the preferred range, the error will be within a fixed percentage. The standard range of resistors are grouped under E series : E3, E6, E12, E24, E48, E96, and E192.įor example, the standard resistances under E12 series are 10Ω, 12Ω, 15Ω, 18Ω, 22Ω, 27Ω, 33Ω, 39Ω, ….till 10MΩ. The International Electrotechnical Commission is an international standards organisation that prepares and publishes international standards for all electrical, electronic, and related products including resistors. Transformer sets need values from maybe 250 up to at least 450 volts types.There are several ranges of resistors available for electronics industry. AC DC AA5 radios all use about the same voltage ratings. If you stuck to AA5 type radios, the variety of electrolytic filter caps would be pretty small too. Unless you want to make a substantial expenditure ahead of time, you will just have to do like alot of us and either settle for using resistors in parallel or series once in awhile, or just waiting for an order in the mail for those last two resistors to finish the job. Alot more than the half dozen or less values you will need for replacing paper caps with plastic types. Actually you will possibly find any of the 10 or 20% type resistors between about 2 meg and 100 ohms in an old tube radio. You would probably find 1k 680 560 470 330 and 220, 150, 100 in one or two watt ranges for those purposes. Values of 1k or below are used for stuff like cathode bias, power supplies, etc. When you get down to 10k and below, you start needing one or two watt values. Most of the time the higher values handle very little power, being tube bias resistors. I would guess that some well used values are like, 2.2M, 1M, 470k, 220k, 100k, 56k, 47k, 33k 22k.

Common resistor values