EMRFD Message Archive 3540

Message	Date	From	Subject
3540	2009-09-10 10:00:34	jmlcs2000	Frequency Counter Chapter 4
The frequency counter that appears on pages 4.29 and 4.30 has worked very nicely in my RX in the past. I just finished building a second one for experimental purposes. In the orginal one that I built I used some MAN4740A Common Cathode displays. However, Mouser no longer carries these displays. I found that the Radio Shack 276-075 is a direct pin for pin replacement for the MAN4740A'S. The only difference is that the MAN4740A displays are .4 in size and the RS displays are .3 in size. Both will fit a 14 pin socket with no prblems. In addition, I used 1K resistors between U7 thru U10 to feed the displays. Finally for the decimal point I used a 1.5K resistor rather than a 1K at Wes's suggestion when I built the orginal counter. I have found that for about $20 or so, this little counter has been a great addition my shack. John, K5IRK
3784	2009-11-19 03:59:02	ep_mand	Re: Frequency Counter Chapter 4
Hello, John: I have the first edition / second print version of EMRFD. Is there an error in schematics (fig. 4.54) - should there be one binary divider stage less? When I analyze the circuit, I get 200ms / 5Hz pulses at U2/Q7, output pin 6. I think 100ms / 10Hz is correct, as in fig. 4.53. Are the outputs of U1 (Q9=13) and U2 (6, 14, 13) right? - Kindly, EePee, OH2NFI.
3785	2009-11-19 08:44:39	ajparent1	Re: Frequency Counter Chapter 4
3786	2009-11-19 08:45:52	ajparent1	Re: Frequency Counter Chapter 4
3789	2009-11-20 02:15:56	ep_mand	Re: Frequency Counter Chapter 4
Of course - I forgot the method though I have made two frequency counters almost 30 years ago! - EePee.