I like to experiment with TTL homebrew computers. Generally I stick with a 1.0 MHZ oscillator frequency, generated with a canned crystal oscillator like the ECS-100AX-010 from Digikey. I've found that 1.0 MHZ is generally about the lowest frequency commonly available in this package. Recently I came across an unusual listing on EBAY for a 1 KHZ canned oscillator. Truthfully, I thought the listing was an error or mistake, but I took a chance and ordered some... Sure enough, that's exactly what they are!

The 1 KHZ oscillators are convenient for doing a quick clock swap on my boards when troubleshooting. Just thought I would pass along the information. Michael