O Nuts of Time, I was recently asked to make a big PDF file of the HP AC-4 counter modules manual that I have had on my website for a few years as a series of jpeg files. So I did...
http://www.nixiebunny.com/hpac4/hpac4.pdf These modules are used in the ancient HP 521 to 524 series of counters. Each module handles one digit. They have four vacuum tubes and either a nixie tube or ten neons in a thermometer arrangement. I have a 521C and a 522B counter on hand but they are a bit too slow to handle the 10 MHz of modern times, having a maximum counting frequency of 200 kilocycles per second. -- --David Forbes, Tucson, AZ http://www.cathodecorner.com/ _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
