## Monday, February 7, 2011

### 【 Weak current College 】 (universal table) the use of a multimeter (upper) 】

Multimeter is the measurement of resistance, voltage, current, and audio power equal meter. A measuring resistance
In the measurement of resistance, should be marked with a "tick" Ω at reading (because of electricity through the header and the measured resistance is not a proportional relationship, so dial scale of resistance is not uniform in size. ) Is the actual value of the measured resistance is equal to the scale ruler reading multiplied by the multiplier knob. In the survey before you will receive two table pen short, rotating zero potentiometer, the pointer in the location of the 0 Ω, and then choose the right gear to ensure accurate measurement. The amount of each change, all to zero. In addition, the resistance measurements, be sure to passive and no other parallel branches. Resistor (or current) measurement has been completed, should be to high voltage switch-gear, this is to prevent the misuse of an ohmmeter (or the current block) measuring voltage of good habits.
B DC voltage and current measurement
Reading should be at the "DC" or "V · mA" symbol scale table, at which point the knob is a DC voltage or current maximum limit (range). Measurement before estimated by measuring the size of the value, then will switch to the appropriate range of stalls. Proportional to the size of the measurement values are read out. Measure the voltage between two points on the circuit, the red pen should meet the test of high potentials, black test pen should receive low potential. Measuring DC current to the ammeter series into the branch, you must first disconnect the measured tributary. If you do not disconnect the slip road take two passengers into the slip road to the table amount of endpoints, actually is used to measure voltage, amperemeter, electricity is consumed.
Multimeter judged the quality of the capacitor
Depending on the electrolytic capacitor size, usually chosen multimeter R× R× 10, 100, R×1K retaining test judgement. Red and black tablepens respectively the negative terminal of the capacitor (before each test, the capacitor discharge), the needle by tilting the table to determine the quality of the capacitor. If the hands quickly swing up to the right, and then return slowly to the left in situ, the capacitor is generally good. If the table is no longer a Cycloid after starting, the capacitor has a rotary breakdown. If the table after the Cycloid up gradually return to a position of stop bits, then the capacitor has leakage. If the table Cycloid, explains capacitor electrolytic push lost capacity has run dry. Some of the leakage of capacitors, using the methods above are not easy to accurately figure out good or bad. When the capacitor voltage value is greater than the multimeter battery voltage value in, according to a Electrolytic Capacitor is charging leakage current is small, the reverse charge leakage current major characteristic, use the R×10K retaining, reverse charging capacitor, look at the table whether the needle stays stable (i.e. reverse leakage current is a constant), which determine the quality, accuracy of capacitor is relatively high. Black table amount received the negative terminal of the capacitor, red table amount received capacitor cathode, hands quickly swing up, and then gradually return to a stationary, then the capacitor is good, all hands in a location remain unstable or stay later gradually and slowly move to the right of the capacitor has leakage, could not continue to use. Hands remain stable in General and 50-200K scale range.
Multimeter as detection tools detect method of integrated circuit