Looked everywhere, but never seen this chem symbol before, plz help

[corbin]

can anyone help me with this, sorry for being so naive, but in this schem. ( http://mujweb.cz/jmartis/qrv4_en_final.png ) what electrical component is located off of pin 4 of the UC that almost looks exactly like a variable resistor. Also, all the capacitor labeling is odd too, 3n3? And if anyone knows a webpage or something that has every symbol on it for everything that would be wonderful! thank you!

 

[ronsimpson]

There is a "pot" variable resistor labeled "power limited set".
There another pot labeled "f" for frequency. It sets the frequency.
3n3=3.3nF (.) Is hard to see and sometimes does not make it through a copy machine. That is why .1uf is often written 0.1uf.

3R3=3.3 ohms
33R=33 ohms
3k3=3.3k ohms

I like the idea of using other than a period. R, C, K, M, ..........

 

[magvitron]

Yeah its a convention 3n3 looks much better to read than 3.3 in computer screen too ron. It reduces errors.

 

[picbits]

I've always viewed those pot symbols (the one with f on it) as a trimmer rather than a conventional potentiometer.

 

[Nigel Goodwin]

I've always viewed those pot symbols (the one with f on it) as a trimmer rather than a conventional potentiometer.

That's because it IS a trimmer

A normal variable resistor has an arrow, as in the one above labelled 'power limit set', the 'f' of course stands for frequency.

The 3n3 etc. is the international preferred way of giving component values, and makes much more sense than '.'

 

[Ian Rogers]

I've always viewed those pot symbols (the one with f on it) as a trimmer rather than a conventional potentiometer.

Same here the bar at the top of the center connector denotes "preset trimmer"