"Avometer " the abbreviation that is avometer, it is our electron an indispensable tool in making. Avometer can measure electric current, voltage, resistor, some to still can measure the enlarge multiple of dynatron, value of value of frequency, capacitance, logistic potential, decibel. Avometer has a lot of kinds, the with digital type avometer of form of the most popular now organic instrument finger (see a picture) . They have an advantage each. To electronic abecedarian, the proposal uses avometer of type of pressing with a finger, because it is a few more familiar to us electronic knowledge principle is very helpful. The principle that we introduce avometer of type of a few mechanical needle below and use method. The fundamental of the fundamental avometer of avometer is the magneto-electric dc ammeter that uses a delicacy (microamper is expressed) the head that make a list. Carry watch head when small electric current, can have voltaic directive. But watch head cannot carry big electricity, so, must in the paralell connection on watch head and series connection a few resistor undertake billabong or step-down, measure the electric current in giving circuit, voltage and resistance thereby. Introduce respectively below. Normal >l measures principle of dc electric current. If graph 1a place is shown, shunt-wound on watch head a proper resistor (call billabong resistor) undertake billabong, with respect to span of OK and patulous electric current. The block of change billabong resistor is worth, can change electric current to measure range. Normal >l measures volts d.c. principle. If graph 1b place is shown, establish ties on watch head a proper resistor (cry times add resistance) undertake step-down, with respect to span of OK and patulous voltage. Change the times block cost that increases resistance, measure range with respect to what can change voltage. Normal > measures alternating voltage principle. If graph 1c place is shown, because watch head is dc watch, when measuring communication so, need to add install and, cluster form half commutate circuit, the repass after having communication rectification becomes dc expresses a head, can measure alternating voltage so according to the size of dc. The method of span of patulous alternating voltage and volts d.c. span are similar. Normal > measures resistor principle. If graph 1d place is shown, on watch head paralell connection is mixed the resistor with proper series connection, string together at the same time receive a batteries, make electric current is passed be measured resistor, according to voltaic size, measurable give resistance. The block of change billabong resistor is worth, with respect to the span that can change resistor. The use avometer of avometer (with 105 model for exemple) if dial is right plan institute is shown. The knob that passes transfer switch will change measure project and measure span. Zero knob uses machinery to maintain pressing with a finger to be in still lie left null. "Ω " zero knob is to be used when measuring resistance, make pressing with a finger aims right null, measure numerical value in order to assure accurate. The measurement of avometer limits is as follows: Normal >l volts d.c. : Divide 5 shelf, 0-6V; 0-30V; 0-150V; 0-300V; 0-600V. Normal >l alternating voltage: Divide 5 shelf, 0-6V; 0-30V; 0-150V; 0-300V; 0-600V Normal >l dc flows: Divide 3 shelf, 0-3mA; 0-30mA; 0-300mA. Normal >l resistor: Divide 5 shelf, R*1; R*10; R*100; R*1K; R*10K Normal > measures resistance: - - join watch club together short circuit first, make pressing with a finger right deflexion turns, immediately is adjusted " Ω " zero knob, make pressing with a finger points to fitly 0. Contact two watches club the resistor that be measured respectively next (or circuit) two end, numerate pressing with a finger is in ohmic graduation mark (the first line) the reading that go up, take the number with this archives mark again, what measure the block of resistor to be worth namely. Block with R*100 for example measure resistance, pressing with a finger points to in 80, the resistance that measures is 80*100=8K. As a result of " Ω " reading of graduation mark wrong department is closer, be hard to be certain, proper ohmic archives should choose when be being measured so. Make pressing with a finger is in the mid or right ministry of graduation mark, such reading are clearer and accurate. Shift gear every time, answer to express two baculine weak point to receive afresh, readjust index arrives null, ability is measured accurate. Measure volts d.c. : - - the volume that estimates the voltage that be measured above all, dial transfer switch next to proper V span, will expressing a club to receive the voltage that be measured " + " upright, negative watch club receives voltage be metricaled " - " upright. Block span number and mark dc symbol according to this next " DC- " graduation mark (the 2nd line) the word of index of place of pressing with a finger that go up, will numerate be measured the size of voltage. If use archives of V300 bend over to measure, the instruction that can read 0-300 directly is numeric. If use archives of V30 bend over to measure, take out of this on simply general graduation mark 300 numbers " 0 " , regard as 30, again ordinal 200, 100 wait for a number to regard as 20, 10 can numerate directly already directive of pressing with a finger is numeric. Measure volts d.c. with archives of V6 bend over for example, pressing with a finger points to in 15, be measured so that voltage is 1. 5 bend over. Measure dc electric current: - - the volume that estimates the electric current that be measured first, dial transfer switch next to appropriate MA span, string together avometer again receive in circuit, if plan institute is shown. At the same time observation mark has dc sign " DC " graduation mark, like electric current span choosing is in 3mA archives, at this moment, should get on exterior graduation mark the number of 300, take out two " 0 " , regard as 3, ordinal 200, 100 regard as 2, 1, can numerate so the electric current that be measured is numeric. Measure dc electric current with dc 3mA archives for example, pressing with a finger is in 100, criterion electric current is 1mA. Normal Align=left> measures alternating voltage: - - the method that measures alternating voltage and measure volts d.c. likeness, because alternating current is done not have,what what differ is, negative cent, when measuring communication so, watch club also does not need branch, negative. Reading method and afore-mentioned the pronunciation that measures volts d.c. is same, it is the number should look mark to have communication sign only " AC " the position of pressing with a finger on graduation mark. The note avometer of use avometer is more accurate instrument, if use undeserved, cause not only measure not accurate and extremely easy attaint. But, want us to master the use method of avometer and note only, discretion is engaged in, so avometer can wear well. Use avometer is to should notice following item: Normal >l measures electric current and voltage to cannot come back poor grade. If go to resistor archives or voltaic archives measuring voltage by accident, with respect to extremely easy burned-out ammeter. Avometer need not when, best archives best friend coming back sheds voltage highest grade, because use,avoid undeserved and attaint. Normal >l measures volts d.c. and dc electric current, notice " + " " - " polarity, do not receive a fault. If discover pressing with a finger leaves,invert, should exchange instantly already the watch is marvellous, lest attaint finger reachs watch head. Normal >l does not know the size of the voltage that be measured or electric current, should use first highest grade, choose appropriate archives again after that will check, lest express needle deflexion excessive and attaint expresses a head. Chooses archives approach the value that be measured more, metrical numerical value heals accurate. Normal >l measures resistance, do not touch with the hand the naked two end of component (or the metallic part with two good watches) , lest human body resistor is as shunt-wound as the resistor that be measured, make measure an outcome not accurate. Normal >l measures resistance, if express two baculine weak point to receive, tone " 0 ohm " knob comes the biggest, pressing with a finger still short of at 0 o'clock, this kind of appearance is created normally, should change new battery square can accurate measure. Normal >l avometer need not when, do not come back in resistor archives, because inside have battery, if do not take care to make two photographs that express a club touch short circuit easily, expend batteries not only, serious when can damage even watch head. CNC Milling
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