ok so i have a bunch of vacuum tubes and i would like to play around with them (i.e. make an amplifier or a radio). i think a diode tube is pretty self explanatory but i'm having some trouble understanding a triode. from what i understand it's the same as a diode tube except that between the cathode and the anode there is a grid where your input would go. what i am wondering (since there is virtually no documentation) is if you were to put a sine wave through the grid then how would it be amplified? does the heater give off electrons the same way one does in a CRT tube providing the amplification or does the tube act more like a transistor? since it's so similar to a diode tube does that mean that it will only let power flow through it one way? i only have a dozen or so 6201 dual tiode tubes as well as a few odd tubes i have yet to identify so i'd like to avoid burning them out. also is it acceptable to mix vacuum tubes and semiconductors (such as diodes) or do they not work well together?