I've been looking in to oscillators and crystals for generating sine and square wave signals but wanted to clarify a few things. Particularly in regards to getting strong signals from them, wave going up and down to atleast close to Vcc(5V, 3.3V, whichever it happens to be) and Gnd, and having currents up to perhaps 100mA if needed for blinking an LED at a specific frequency, to then use elsewhere within circuit designs.
Many crystals seem to be primarily intended for clocking a microcontroller, attach the two ends to specific pins on the microcontroller, and then attach capacitors of a certain approximate size from these ends to Gnd and they act to provide a clock. But if you want to use a crystal in a more customised circuit design this isn't much use.
I've seen some analogue designs with transistors, resistors and capacitors aiming to get a signal out from an oscillator crystal, but they look like they'd be quite sensitive to inaccuracies in the resistor and capacitor's values. Surely the idea of crystals with high precision ratings for the accuracy of their frequency is that you can sidestep al worries over R and C accuracies?
I've also seen some designs using a crystal with a pair of NOT gates, and think for these that the capacitor values used should be tolerant of inaccuracy, but can't quite understand why. Also these seem to be for square waves only, I'd like to know hw to construct sine and triangle wave alternatives too.
I've seen some 4 pin oscillators for sale, usually with a Vcc, Gnd, enable and output pin. Are these a pretty rare component to use though, the kind which only comes in more unusual sizes from one or two manufacturers, the sort of part you can't often find generic substitues for? Also these all look pretty big in board space consumption, several times the size of a 2 pin crystal (even a through hole canned version). And again only give square waves it seems, not sines or triangles.
Thank you