When testing, use the ohm gear of the multimeter (depending on the nominal resistance value to determine the gear, generally R1 gear), which can be operated in two steps: first, test at normal temperature (indoor temperature is close to 25 degree ), use alligator clips instead of test pens to clip them separately. Measure the actual resistance value of the two pins of the PTC thermistor, and compare it with the nominal resistance value. If the difference between the two is within ±2Ω, it is normal. If the actual resistance value is too different from the nominal resistance value, it means that its performance is poor or damaged. Secondly, heating test, on the basis of normal temperature test, the second step test - heating test can be carried out, a heat source (such as an electric soldering iron) is heated close to the thermistor, and the multi-function indicator is observed. It is seen that the multi-function indicator changes with the increase of temperature, which indicates that the resistance value is gradually changing (the NTC resistance value of the negative temperature coefficient thermistor will become smaller, and the PTC resistance value of the positive temperature coefficient thermistor will become larger) , When the resistance value changes to a certain value, the displayed data will gradually stabilize, indicating that the thermistor is normal. If the resistance value does not change, it indicates that its performance has deteriorated and cannot be used continuously.
Ba chóir na pointí seo a leanas a thabhairt faoi deara le linn na tástála: (1) Tomhaiseann an monaróir Rt nuair a bhíonn an teocht chomhthimpeallach 25 céim, agus mar sin nuair a bhíonn Rt le iliméadar á thomhas, ba cheart é a dhéanamh freisin nuair a bhíonn an teocht chomhthimpeallach gar do 25 céim go dtí an testability a chinntiú. iontaofacht. (2) Ní rachaidh an chumhacht tomhais thar an luach sonraithe chun earráidí tomhais de bharr éifeacht teirmeach na reatha a sheachaint. (3) Tabhair aird ar oibriú ceart. Agus tú ag tástáil, ná pinch corp an teirmeastóra le do lámha chun cosc a chur ar theocht an chorp daonna tionchar a imirt ar an tástáil. (4) Bí cúramach gan an fhoinse teasa agus an teirmeastar PTC a dhéanamh ró-dhúnadh nó déan teagmháil dhíreach leis an teirmeastar chun é a chosc ó scalladh.
