Single Display LED Frequency Counter

  
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As equipment becomes increasingly more compact, designers are often obliged to follow suit by reducing the size of displays. At some point, the usefulness of the display can become compromised. I, for one, dislike having to peer intently at tiny displays in an attempt to read vital information, if only because it serves as a reminder that my eyesi
Single Display LED Frequency Counter - schematic

ght is no longer the 20:20 model of optical perfection I`d like to pretend it once was. In the search for suitable displays for compact equipment, I explored using a single seven-segment LED to display multiple digit information. If successful, this could both deliver the required functionality and minimise display size. With a suitably large LED digit, information could also be seen from some distance without the need for eye strain. But is such a display practical in real applications This little frequency counter suggests that it is. It is a lightweight and remarkably rugged portable frequency counter which will readily operate up to 65 MHz. While using only a large single LED display, it displays a frequency with five digits of resolution (i. e. to the nearest kHz) in a package which can be easily carried in a shirt pocket. Some initial tests showed that displaying multi-digit frequency measurements on a single display is best handled by displaying the information in a series of three digit bursts. Any more information than this seemed to introduce the potential for confusion. In this case, each set of three digits is sequentially displayed for about 300mS per digit with a short inter-digit pause of about half this duration. This is followed by a longer pause of about a second to clearly flag the end of the three digits of information. There is clearly something of a tradeoff in this timing. A longer duration for each...



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