Recently I stumbled across Cadet schematics and I wonder why they have these capacitors and diodes near power in. Is it universal solution that I should use in all my module designs?
The diodes are for reverse polarity protection
The caps are to remove AC noise from the powerlines. (I hope I formulate this correctly)
The big Electrolythic 10uF ones are located near the power header, the ceramic 100nF as near a possible to each IC.
These components are pretty standard , so you should use them !
The L1 and L2 are Ferrite beads, they filter EMF noise. (which is mostly useful for video circuits. For audio I usually put 10r resistors in place there, acting as fuses.
Thanks! I have one more question; is this TL431 some way protected from overheating? I read that voltage converters can get really hot.
no, the TL431 makes a 2.5v reference. It is not getting hot, as far as I know
It is not used as a power source
Some of the LZX Cadets use a LM78l05. to power CMOS IC’s. Those might get a little hotter, but not so much that you need a cooling fin.
The TL431 in this circuit is just used a voltage reference, rather than a fixed voltage current source (i.e. voltage regulator). The only thing in the circuit which uses it is an input on U1.1, which draws negligible current. It doesn’t get hot at all.