This is a complicated subject. Do you just want blinking lights or do you want a useful tool? There are some standards out there but the real issue becomes ballistics. How fast does the needle (or LED's) move? Hold times? A crappy meter is worse than no meter at all.
So metering design depends on what you are trying to measure. If its signal level on digital recording, you need to make damn sure you don't run out of bits. If its for a power amp, clipping / power output, thats a different circut.
Something out of theme...sorry
Yes i am a Iron Maiden fan but not fanatical.I just love lyrics and quality or knowledge thay play on instruments.
I just got bored of that shitty commercial stuff,i like Dire Straits and similar music too.