diodes for rectification

Thread Starter

Kelko

Joined Oct 1, 2020
24
I was wondering if anyone could help me. I'm using a full wave bridge rectifier but the input AC has a 5Vrms and a frequency of 100kHz what type of diode should I use?
 

crutschow

Joined Mar 14, 2008
25,976
atm the output load is 10kohms
So it's just a pure resistive load, no capacitance?
If so you could use 4 MOSFETs for the bridge which will have near zero voltage drop in the forward direction.

LTspice simulation of example circuit below:

1607146724020.png
 
Last edited:

ronsimpson

Joined Oct 7, 2019
1,121
what type of diode should I use?.... 100kHz ......5V
Do not use 1N4007. It was designed for 50/60hz and is too high voltage. Generally high voltage diodes have high forward voltage drop.
Use "small signal" diode. 1N4148, 1N914. Fast and good for 200mA.
Because 5V is small you might consider Schottky. BAT54 20V 300mA. The forward turn on voltage is very low. Less power/signal lost.
 

MisterBill2

Joined Jan 23, 2018
7,679
Certainly the current would matter, but if the load is indeed 10,000 ohms the current will not be much. OR the TS can use those spice diodes that show zero forward voltage drop. For that low a current at that supply voltage a 1N914 diode should be adequate. With the application unknown and the source resistance at zero there is not much else to say. All manner of guesses are available, though.
 

crutschow

Joined Mar 14, 2008
25,976
You can also use the B-C junction of 2n2222 or similar BJT's
When transistor radios first came out, the manufacturers would say how many transistors they had, implying that the more transistors, the better the radio.
Some would then use a transistor for the AM diode detector, so they could say they had one more transistor then the competition.
 

AlbertHall

Joined Jun 4, 2014
10,764
When transistor radios first came out, the manufacturers would say how many transistors they had, implying that the more transistors, the better the radio.
Some would then use a transistor for the AM diode detector, so they could say they had one more transistor then the competition.
The valve radio manufacturers did much the same with EB41 et.al.
 

MisterBill2

Joined Jan 23, 2018
7,679
Why mention ancient history here? The TS is asking about using diodes for a low voltage circuit. Transistors as detector diodes is about the 1962 era, which puts it about 58 years ago. Also, those were germanium transistors, which are not common currently.
As for diode tubes being only detector diodes in radios, that must certainly predate the "all American Five" tube radio from the mid 1950's era. Or been from another part of the world. The 12AT6 and 12AV6 were the dual diode plus triode tubes for those radios.
 

Ramussons

Joined May 3, 2013
911
I don't know how my suggestion went somewhere else.........
The TS wants a diode for 100 KHz, 5 Volts RMS, about 50 mA....

My suggestioin was to use a 2N222 with the Collector and Base Shorted so we have a Diode with the CB as the Anode and Emitter as the Cathode.
 
Top