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Common diodes frequency?
001:
Hi
I`m looking for datasheet like https://www.vishay.com/docs/88755/uf4001.pdf
But no info what frequency diodes rated :-//
Is it some wellknown thing what I did`nt know?
capt bullshot:
Yes, diodes aren't rated for frequency but for junction capacitance, turn-off charge and turn-off delay, repetitive peak current and the like.
By looking at these parameters, one can bin diodes roughly to
- Rectifiers (line frequency) - robust with large peak current but also large turn-off delay/charge (if specified at all) - not useful for frequencies above a few kHz
- Fast rectifiers (SMPS) - low turn-off losses (due to low turn-off charge/delay), medium to low peak current in comparison to steady current, typical frequencies up to few 100kHz
- General small signal - low capacitance, low steady forward current, usually working fine to MHz range
- All kind of RF and other specials - read the datasheet to find out the intended application and frequency range
The UF400x is of the fast rectifier kind, not really suitable as an (power) line rectifier (that would be the 1N400x)
SiliconWizard:
What exactly would you expect to see?
The junction capacitance value would be a good start to model the frequency response in a given circuit.
Note that with through-hole packages, the parasitic inductance may not be negligible and also something to take into account.
A "simplified" model would be something like: a series inductor, a series resistor, and an ideal diode in parallel with a capacitor.
001:
Thanx a lot!
Sorry my question is wery mudy :palm:
The problem is about AC meter https://www.eevblog.com/forum/projects/shottky-diodes-instead-of-germanium-in-old-analog-meter/
001:
--- Quote from: capt bullshot on October 24, 2019, 01:52:27 pm ---
The UF400x is of the fast rectifier kind, not really suitable as an (power) line rectifier (that would be the 1N400x)
--- End quote ---
Some people "upgrade" 1N400x with UF400x and caps across it. Why? :-//
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