What does HFE mean on a multimeter?
The HFE setting on the multimeter measures the current amplification factor of the transistor. This kind of meter has a socket for measuring the transistor. The hFE level is mainly used to measure the magnification β value. Before measuring, you must first determine whether the transistor is PNP or NPN type, and determine the polarity of each pin.
How to use: When measuring, insert the triode into the corresponding polarity jack, and you can read the current amplification factor of the triode.
Extended information:
The meter head of the multimeter is a sensitive ammeter. The dial on the watch head is printed with various symbols, scales and numerical values. The symbol A-V-Ω indicates that this meter is a multimeter that can measure current, voltage and resistance.
There are multiple scale lines printed on the dial. The one marked with "Ω" on the right end is the resistance scale line. The right end is zero and the left end is ∞. The scale value distribution is uneven. The symbol "-" or "DC" represents direct current, "~" or "AC" represents alternating current, and "~" represents the scale line shared by AC and DC. The several rows of numbers under the scale line are the scale values corresponding to the different gears of the selector switch.
Working principle of multimeter:
The basic principle of a multimeter is to use a sensitive magnetoelectric DC ammeter (microampere) as the meter head. When a small current passes through the meter, there will be a current indication. However, the meter head cannot pass large current, so some resistors must be connected in parallel or series with the meter head to shunt or reduce the voltage, so as to measure the current, voltage and resistance in the circuit.
What do hfe, PNP and NPN on the multimeter mean?
HFE is the abbreviation of the triode DC current amplification factor, which is the current amplification factor of the triode; PNP and NPN represent two types of triodes.
When the triode is on, IE=(amplification +1)*IB has nothing to do with ICB. When ICB=0 and ICB>0, there may be a problem with the triode, so when the triode is working normally, whether it is working in the amplification zone or the saturation zone ICB =0. When UEB>0.7V (silicon) (germanium 0.2V) and RC/RB<amplification factor, the transistor works in the saturation zone, otherwise it works in the amplification zone.
The difference between a PNP transistor and an NPN transistor is that the directions of the two PN junctions are inconsistent.
PNP is a common cathode, that is, the N junction of the two PN junctions is connected as the base, and the other two P junctions are used as the collector and emitter respectively; the triode is marked with an arrow pointing inward in the circuit diagram. NPN is the opposite.
