/diy/ - Do It Yourself

Do I need this extra inverter after the oscillator? I'll be using it to clock shift registers. Also I hope I can use the same circuit for a 32.768kHz crystal.

Why is it so hard to make a crystal oscillator oscillate on a breadboard. I built a classic Pierce oscillator with an 8MHz crystal using at first a 3.3M and later a 1M load resistor. I tried a load capacitence of 22pF and 33pF and even whacked in some reverse biased 1N4148's with about 1pF of junction capacitence instead of capacitors and I just couldn't get it to start. I tried it with a 1k resistor in the position of R2 in the pic and I tried it without it and still couldn't get it to start. I kept all the lead lengths as short as possible. I tried using 74LS04 for the inverter, then I tried a 74LS14 instead. No matter what I do I just cannot get it to work and I don't know why.