April 7, 2018 - New - Prescaler Partial kit
if you would like ordering information. More info and new pictures to come.
The kit includes the 5 volt regulator, two .1 uf bypass capacitors, two
1000 pf coupling capacitors, a 51 ohm input resistor and an 820 ohm
output loading resistor along with the circuit
board. The passive components are 1206 sized while the prescaler
is in an 8 pin SO package - these are both relatively easy to
solder but the kit is not for surface mount kit beginners.
The circuit board is about 1.3 by 0.7 inches and has
one mounting hole sized for 4-40 hardware (1/8 inch) or metric M3.
The Prescaler partial kit is a lower cost version of the original Prescaler kit
which is identical EXCEPT that the prescaler chip itself is NOT supplied. This chip, the MC12080 from On Semiconductor
is still available from distributors like Digi-key or Mouser.
Avoid vendors on ebay, there are a lot of counterfeit versions of the MC12080. Some
may divide by 2 (there are several chips which are pin compatible with the MC12080 but NOT function compatible). Some may do absolutely nothing.
The board also now has a solder mask and
Price of the Prescaler partial kit is $4 plus postage/handling
Prescaler is a simple divide by 10 ECL circuit which can be
used to extend the range of most PIC based frequency counters from
50 MHz up to 500 MHz. The kit uses surface mount components except
for the 78L05 regulator.
Printed manuals available for an additional charge or
save money by downloading (Right click/save target as)
and printing the prescaler kit
and hookup diagram
all in Adobe Acrobat (.pdf) format. also a diagnostic measurements for troubleshooting text file
Is it normal for the prescaler to output a frequency when the
input is unconnected ?
Yes, my prescaler does this at roughly 20 MHz.
If this bothers you, Earl, N8ERO, suggests this fix, add a 100 k ohm
resistor across capacitor C1. This results in slightly lower sensitivity.
What is the sensitivity of the prescaler ?
Here is some
customer measured sensitivity data.
For larger quantity purchases, to combine with other items, for DX purchase price
or for any other questions, please send an email to me, Chuck Olson, WB9KZY at:
with your question or the items you want and we'll email you a Paypal invoice.