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About diodes
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How do diodes work?
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Areas of use of diodes
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How to find the right diodes
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FAQ - Frequently asked questions about diodes
How do diodes work?
A diode functions like a backstop valve: The current can only flow in the direction of flow, the reverse direction of the diode.
In the construction of a diode, a functional basis is either a p-n-doped semiconductor crystal or a metal-semiconductor junction . The p-n or material transition determines the one-sided flow direction of the moving charge carriers when the semiconductor diode passes.
Bit memory: If the positive pole is at the anode, current flows. If the negative pole is at the anode, the diode is locked.
There must be sufficient voltage in the forward direction for the diode to flow current . This minimum voltage value is referred to as the threshold or spin voltage of the US diode or, interchangeably, UF.
The current-voltage characteristic describes the connection between electrical current and voltage in two-pole semiconductor diodes. It is called the I-U characteristic or U-I diagram.
The graph of the technical drawing is not linear for diodes. The current flow only increases when the threshold voltage is applied to the anode. The actual current-voltage characteristic curve of a diode is product-specific and also temperature-dependant .
Areas of use of diodes
The use of conventional diodes has three main objectives:
- Rectification of alternating voltage
- Limiting voltages
- Stabilization of tensions
In addition, the semiconductor transition of diode designs is also used for other purposes, for example, the Zener diodes, whose function is explained below.
How to find the right diodes
Find suitable diodes for your application by first selecting the right category of diodes in our online shop and then filtering them according to further selection criteria such as forward voltage, reverse voltage and operating temperature.
Standard, HF & Power Diodes
The standard range of diodes includes semiconductor diodes such as rectifier diodes, silicon diodes, germanium diodes, Avalanche diodes, Schottky diodes or high-voltage diodes.
Diode assortments
In this category you will find a large number of different diode types.
Capacitance diodes
Capacitance diodes are also called tuning diodes, because by changing the applied voltage, the capacitance can be controlled . This eliminates the use of the previously used, much larger rotary capacitors.
Schottky Diodes
These models do not have a p-n transition, but instead have a blocking metal-semiconductor transition , the Schottky contact . They function as rectifiers and have a much faster transition from forward to reverse operation than conventional diodes. Your reverse current is very temperature-dependant.
Zener diodes
Zener diodes, in short Z diodes, are characterized above all by their breakthrough voltage, the Z voltage, from which a avalanche-like breakthrough of the voltage can be observed. They are usually operated in reverse direction, in forward direction Zener diodes function like normal diodes. They are used to stabilize the voltage.
Suppressor diodes
Suppressor diodes, also known as transient absorption Zener diode (TAZ diode) or transient voltage suppressor diode (TVS diode), function as overvoltage protection and protect electronic components from excessive voltage pulses in the circuit or from external influences such as lightning strikes. When their threshold voltage is reached, these diodes conduct the current of the false pulse into a parallel circuit and thus pass the component to be protected.
Tip: In the diode sale you will find particularly favorable and currently discounted offers for diodes in our online shop. Be inspired by the wide range of products you can browse. With many diodes, you get a volume discount as standard when you buy larger quantities. You can find information on this in the selection lists in the right column or in the respective sub-pages of specific products.
FAQ - Frequently asked questions about diodes
When installing in a circuit, how do I recognize which side is the cathode and which side is the anode of a diode?
There are basically two systems for labeling the polarity and other electrical properties for diodes. In the American JEDEC marking, the cathode has the widest of four rings. For Pro-Electron, the European marking, two wide rings are on the cathode side. Additional letters, numbers and color codes provide information about other electrical characteristics of the respective diode. Caution: In addition to the two markings presented, there are many other systems for coding the polarity of diodes. If in doubt, consult the manufacturer.
Why do I have to observe the operating temperature for diodes?
If a diode of junction temperature is mentioned in the specific product data sheet, it is not the ambient temperature for continuous operation, but rather temperature peaks that the component can withstand for a limited period of time. Exceeding the operating temperature can lead to the thermal destruction of the semiconductor elements in the diode. Both the ambient temperature and the heating by the applied electrical voltage can cause such damage if the diode cannot dissipate its heat loss sufficiently.