Class = "keylink" > diode "D" is commonly used in the circuit with digital representation, such as: D5 said Numbers for 5 diode.

1, role: the main characteristics of diode is a one-way electrical conductivity, which is under the action of forward voltage, conduction resistance is small; While under the effect of reverse voltage on resistance greatly or infinity. Because of diode with the above properties, cordless telephone, to use it on rectification, isolation, voltage regulator, polarity protection, coding modulation, frequency modulation and static noise control circuits.

Telephone do you use in the crystal diode according to the function can be divided into: (e.g., 1 n4004), isolation diode rectifier diode (e.g., 1 n4148), schottky diode (such as BAT85), light-emitting diodes, zener diodes, etc.

2, recognition methods: identification of a diode is very simple, small power diode N pole (cathode), in the diode looks mostly adopts a circular color standard, some diodes also use special symbols to represent a P (positive) or N (cathode), also have use symbols for "P", "N" to determine of polarity of the diode. Across the electrodes of light-emitting diodes (leds) from the length of the pin to identify, long feet is positive, negative short feet.

3, test, note: when using a digital multimeter to measuring diode, red pens and pick up the positive, of the diode black pens and diode of the cathode, the measured resistance is the diode is the guide of value, the pointer multimeter pens and connection of the reverse.

Transistor "Q" is commonly used in the circuit with digital representation, such as: Q17 said Numbers for 17 triode.

1, characteristics: transistor (triode) is an internal contains two p-n junction, and special device capable of amplification. It divides the NPN and PNP two types, the two types of triode can compensate for each other from the job characteristics, the so-called OTL circuit of the pipe is used by PNP and NPN pairing.

That is commonly used in telephone PNP transistors are: A92, 9015 model; NPN transistors are: A42, 9014, 9018, 9013, 9012 models.

2, transistor amplifying role is mainly used for amplification circuit, there are three kinds of connection in the common circuit. Three kinds of connection for comparison, the transistor circuit has the characteristics listed in the table below, for your reference.