Sunmate - selection of diodes — SUNMATE
Sunmate - selection of diodes
(1) Rated forward working current
The rated forward working current refers to the maximum forward current allowed by the diode during long-term continuous operation.
(2) Maximum surge current
The maximum surge current is the excess forward current allowed to flow. It is not a normal current, but an instantaneous current. Its value is usually about 20 times of the rated forward working current.
(3) Maximum reverse working voltage
When the reverse working voltage applied at both ends of the diode reaches a certain value, the tube will break down and lose unidirectional conductivity. In order to ensure the safety of use, the maximum reverse working electric value is specified. For example, the reverse withstand voltage of ln4001 diode is 50V, and the reverse withstand voltage of ln4007 is 1000V.
(4) Reverse current
Reverse current refers to the reverse current flowing through the diode under the action of specified temperature and maximum reverse voltage. The smaller the reverse current, the better the unidirectional conductivity of the tube. The reverse current is closely related to the temperature. For every 10 ℃ increase in temperature, the reverse current will double. Silicon diode has better stability than germanium diode at high temperature.
(5) Reverse recovery time
When changing from forward voltage to reverse voltage, the current generally cannot be cut off instantaneously, and it needs to be delayed for a little time, which is the reverse recovery time. It directly affects the switching speed of the diode.
(6) Maximum power
The maximum power is the voltage applied to both ends of the diode multiplied by the current flowing. This limit parameter is particularly important for zener diodes, etc.
(7) Frequency characteristics
Due to the existence of junction capacitance, when the frequency is high to a certain extent, the capacitive reactance is small enough to short circuit the PN junction. The diode loses unidirectional conductivity and cannot work. The larger the PN junction area is, the larger the junction capacitance is, and the more it cannot work at high frequency.