Help with diode type please

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regmalone

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I'm wiring a simple data transfer interface which needs the voltage dropped from around 5-7v to no more than 3.7v. The schematic says I need a diode but which kind? Do they come in sizes, ratings etc?

I'm a complete novice but I hope someone here can point me in the right direction. Here it is:

 

Hi,

Diodes like 1N4148 / 1N914 100ma and 1N4001 to 1N4006 1amp, will drop the voltage by about 0.7vdc.
There are other types of diodes that will drop the voltage by just 0.2vdc

You can buy them for a few pence from Maplin stores or any electronics shop.

Being as you are talking about dropping 5v to 3.7 you will need at least two diode in series.

Before connecting both units together you would be wise to test the voltages before and after the diodes to ensure the voltages are ok


However I do not know that equipment, and if the author cannot clearly show what is actually needed I would be dubious about connecting anything like that up, unless you can get some first hand confirmation of what is needed to guarantee it works.
 

    regmalone

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Thanks for the reply and I appreciate the words of caution. As I understand, the parallel port can be used for things like this but the output isn't a steady 5v, hence the diode. Another option is to use a 9v battery as the power source and step that down too. Obviously, I don't want to blow my parallel port or my Playstation's memory card. Just saves spending £15-£20 on a USB unit which does a similar thing.

Whatever, I'll make sure I check the voltage as I go along!

In case anyone's interested, I found this really informative page on using your computer's parallel port for projects: https://www.epanorama.net/circuits/parallel_output.html

Thanks again, wp.
 

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