EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: johm on September 06, 2016, 09:59:51 am
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Is it a good design practice to place two or more germanium diodes in parallel to achieve a lower forward voltage drop? Does increased capacitance limit bandwidth? Is therefore more current needed to bias them properly?
Thank you
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Is it a good design practice to place two or more germanium diodes in parallel to achieve a lower forward voltage drop? Does increased capacitance limit bandwidth? Is therefore more current needed to bias them properly?
With putting anything in parallel (cells, resistors, diodes, transistors, etc) the problem is ensuring the current is shared equally between unequal devices.
With putting anything in series (cells, resistors, diodes, transistors, etc) the problem is ensuring the voltage is shared equally between unequal devices.
How you acheive that depends on the specific application and its requirements. (Numerical requirements, no adjectives allowed : )
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No. two diodes does not have the same forward voltage for a given current. one will conduct more than the other
for example: LEDs in parallel.
If you need a lower Vf use a different diode technology (schottky) or use an opamp as a precision rectifier
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Is it a good design practice to place two or more germanium diodes in parallel to achieve a lower forward voltage drop?
Its possible that splitting up current would yield lower Vfd, but real issue is significant diode to diode
threshold voltage match. The only way around that would be to screen / bin diodes for matching.
Does increased capacitance limit bandwidth?
Depends on circuit design, how the diode is being used. Cannot make a categorical statement here.
Is therefore more current needed to bias them properly?
No, not necessarily.
Regards, Dana.