What is ESR METER ?

Written by Jestine Yong

All capacitors have a certain amount of resistance torepparttar passage of AC current. ESR (Equivalent Series Resistance) isrepparttar 138979 sum of all internal resistances of a capacitor measured in Ohms. An ideal capacitor has ZERO ohms ESR. Fromrepparttar 138980 diagram below you can see a resistor in series with a “PERFECT CAPACITOR”. The value ofrepparttar 138981 resistor is called ESR. Electrolytic Capacitors have a tendency to increase its ESR overtime due to drying or corrosion. High ESR is a frequent problem in today’s electronic circuit. Even a 1 or 2 ohms rise in ESR can cause complicated problems. Under normal conditionsrepparttar 138982 ESR has a very low value, which stays that way for many years unlessrepparttar 138983 rubber seal is defective, in which caserepparttar 138984 electrolyte’s water component gradually dries out andrepparttar 138985 ESR creeps up with time. The increase in ESR increases both voltage drops withinrepparttar 138986 capacitor andrepparttar 138987 heat, produced inrepparttar 138988 capacitors due to resistive heating. If you don’t check for ESR, you may be in for a “TOUGH DOG” repair. High ESR isrepparttar 138989 first sign of a capacitor failure. High ESR will cause complete circuit failure, over heating of capacitor, loading ofrepparttar 138990 circuit, overstressing of other circuit components and other undesirable effects. Why should I use an ESR?

Because measuring an electrolytic capacitor with an analog or digital capacitance meter can MISLEAD a technician into believing that a defective capacitor is good. This can waste your precious time and you are unable to repairrepparttar 138991 equipment. Which means you can’t charge your customer! If you don’t test for ESR onrepparttar 138992 capacitor, you will always missrepparttar 138993 bad capacitor. Normally, these bad capacitors have high ESR reading which your normal multimeter or digital capacitance meter can’t measure. Only by usingrepparttar 138994 ESR meter, you will be able to measurerepparttar 138995 ESR onrepparttar 138996 capacitor and you will not be fooled by capacitors with bad ESR. ESR meter can even work IN-CIRCUIT, which means you don’t have to solder outrepparttar 138997 capacitor in order to measure it using normal capacitor tester, which would not be accurate anyway. Do you know that ESR meters can perform other wonders besides checkingrepparttar 138998 ESR of a capacitor? Some digital ESR meter haverepparttar 138999 features of checking:

What is a Fuse ? And how to test it.

Written by Jestine Yong

A fuse is a very thin wire, which either melts or vaporizes when too much current flows through it. The thin wire may be made of aluminum, tin-coated copper or nickel. The resulting open inrepparttar circuit stops current flow. In electronic equipment, most fuses are cylindrical glass or ceramic type with a metal cap at each end! The current rating also can be seen in one ofrepparttar 138978 two metal end caps. There are two popular physical sizes: 1 – ¼ X ¼ - inch and 5X20mm. The 1 – ¼ X ¼ - inch size is used in many automobiles. You’ll find both sizes in many electronic equipment, butrepparttar 138979 smaller 5 X 20mm has become more common. Fuses are available with current ratings from 1/500 Ampere to hundreds of amperes.

Purpose of Fuses

The purpose of a fuse is to open an electronic circuit when current flow exceeds a certain amount, determined byrepparttar 138980 rating ofrepparttar 138981 fuse. Opening a circuit under high current conditions can save electronic components from damaged and prevents overheating, which could cause a fire.

Types of Fuses

There is two basic types of fuses: fast acting and slow blow. The fast acting type will open very quickly when their particular current rating is exceeded. This is important for analog meter movements, which can quickly be destroyed when too much current flows through them, for even a very small amount of time. Slow blow fuse have a coiled construction inside. They are designed to open only on a continued overload, such as a short circuit. The purpose of coiled construction is to preventrepparttar 138982 fuse from blowing on just a temporary current surge.

Do not use a slow blow fuse in place of a fast acting fuse. It may not open fast enough to prevent components damage under a high current condition. It’s not harmful to replace a slow blow fuse with a fast-acting fuse, but it will probably open up unnecessarily every now and then whenrepparttar 138983 equipment is first switch on. A blown fuse can tell you something about your service problem. Oftenrepparttar 138984 glass case ofrepparttar 138985 fuse appears clear, and you can still seerepparttar 138986 broken pieces ofrepparttar 138987 fuse element. This means you haverepparttar 138988 kind of problem that causes a slow, gradual overload onrepparttar 138989 power supply. Some fuses even die of old age. But ifrepparttar 138990 inside ofrepparttar 138991 glass fuse is discolored, and there is no trace ofrepparttar 138992 fuse element (the center connector), you know thatrepparttar 138993 center connector was destroyed quickly and violently, using a lot of heat. The fault was a short circuit or other problem that caused a lot of current to flow very quickly.

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