31-12-2016, 09:42 AM
Hi.
Both of Andy's circuits should test the majority of crystals. In addition though I'd say a lot of older crystals that have been lying unused for many years may not work, I've no idea why this phenomenon occurs, some of the ones I have are the big chunky ones that come apart, they have springs to hold the contact onto the crystal and look 100% perfect but wont respond on any circuit valve or semiconductor.
If you are intending to replicate my micro TX project then most of the more up to date crystals will work fine, a series fed crystal being the right choice.
I also have one of the bangood frequency counters which has the facility to test crystals and it gives the fundamental frequency of the crystal on the display, again it's fussy and prefers relatively modern crystals.
Both of Andy's circuits should test the majority of crystals. In addition though I'd say a lot of older crystals that have been lying unused for many years may not work, I've no idea why this phenomenon occurs, some of the ones I have are the big chunky ones that come apart, they have springs to hold the contact onto the crystal and look 100% perfect but wont respond on any circuit valve or semiconductor.
If you are intending to replicate my micro TX project then most of the more up to date crystals will work fine, a series fed crystal being the right choice.
I also have one of the bangood frequency counters which has the facility to test crystals and it gives the fundamental frequency of the crystal on the display, again it's fussy and prefers relatively modern crystals.
