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.