How to use multimeter HFE
Multimeter measurement of voltage, current and resistance function is realized through the conversion circuit part, and the measurement of current and resistance are based on the measurement of voltage, that is to say, the digital multimeter is expanded on the basis of the digital DC voltmeter. The converter changes the analog voltage quantity which changes continuously with time into digital quantity, then the electronic counter counts the digital quantity to get the measurement result, and then the decoder display circuit displays the measurement result. The logic control circuit controls the coordinated work of the circuits and completes the entire measurement process in sequence under the action of the clock.
The HFE file on the multimeter is to measure the crystal transistor current amplification, this kind of table has a measurement of the crystal transistor socket, the measurement of the transistor inserted into the corresponding polarity jack, you can read the transistor's current amplification.
Many small multimeter with a transistor gear and tube base, with its measurement of transistor DC amplification B, penetration current Icbo more convenient. But some circuits on the transistor requirements are more stringent, relying solely on the measurement of the above parameters can not meet the requirements, often measured B, Iceo, ICbo. normal, installed but not work properly, so that the maintenance work has taken a lot of detours.
Practice found that the V-l01 multimeter as an example. Three-stage tube according to normal methods in the multimeter measured B, if normal, and then in turn measure the "reverse amplification", if the needle indicates swing less than 5 times (the original HFE scale), indicating that the tube can be used, such as the needle indicates a larger swing, measured the tube can not be used in less stringent requirements of the circuit.
