So when you work with analog electronics, you learn that voltage is your friend. Playing with +/- 12V (a 24V range) for "analog logic" is innately cleaner than playing with 0V to 5V (5V range).
Lets say you make a design that has +/- 1V error. On the 5V circuit, that's 20% error. But on the +/-12V circuit, it is only 4.1% error. (Going much better than 5% or 1% error is nonsensical. Most resistors you'll buy are 5% error, and capacitors are maybe +/- 20% error). So you can see, +/-1V error is acceptable on +/-12V circuits, but maybe unacceptable on 5V circuits.
If precision is important, there are 1% or 0.1% resistors available, as well as matched-resistors (which have say 1% error, but all the resistors have the same degree of error, so your "proportions" remain consistent. You can manually-match resistors together with an accurate ohm-meter as well)
As such, +/- 12V is simply easier to make "precise" electronics on. Of course, the downside is that you've got leakage all over the place (more voltage means more power-draw)
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But now its 2021. Most parts, even extremely cheap "Jellybean" parts like the LM358, have low errors and low-bias. And USB's popularity as a 5V delivery mechanism has grown, everyone has a USB plug somewhere to use as the basis of electricity experiments.
So while electronic engineers way back played with +/-12V, today the assumption is that you play with 0V to 5V.
Lets say you make a design that has +/- 1V error. On the 5V circuit, that's 20% error. But on the +/-12V circuit, it is only 4.1% error. (Going much better than 5% or 1% error is nonsensical. Most resistors you'll buy are 5% error, and capacitors are maybe +/- 20% error). So you can see, +/-1V error is acceptable on +/-12V circuits, but maybe unacceptable on 5V circuits.
If precision is important, there are 1% or 0.1% resistors available, as well as matched-resistors (which have say 1% error, but all the resistors have the same degree of error, so your "proportions" remain consistent. You can manually-match resistors together with an accurate ohm-meter as well)
As such, +/- 12V is simply easier to make "precise" electronics on. Of course, the downside is that you've got leakage all over the place (more voltage means more power-draw)
---------
But now its 2021. Most parts, even extremely cheap "Jellybean" parts like the LM358, have low errors and low-bias. And USB's popularity as a 5V delivery mechanism has grown, everyone has a USB plug somewhere to use as the basis of electricity experiments.
So while electronic engineers way back played with +/-12V, today the assumption is that you play with 0V to 5V.