"Bill Janssen" wrote in message
...
Hans Summers wrote:

[snip]



Not familiar with the chips you are using but you should use the lowest
frequency oscillator possible.
Maybe try the 32 + KHz crystal

Bill, I am aware that CMOS current consumption is dependant on operating
frequency. However the simplicity of the design demands a clock frequency
which is a power-of-two multiple of 1KHz. Otherwise the counting range would
have to be other than 0 to 99.5KHz. This counting range is perfect for
amateur bands, the offset off the band edge or next multiples of 100KHz.

In any case the counting frequency of the 74HC4040 in my tests was very
similar to the 74HC4060 timebase since I was using an 80m VFO. But the
current consumption of the 74HC4040 was negligble. Therefore there must be
something about the oscillator configuration which is causing the high
current consumption.

That's why I'm wondering if there are other, more power-efficient ways of
making an oscillator. Bear in mind that a 32768Hz watch crystal is only 125
times slower than my 4096KHz crystal. Assuming proportionality that's about
25uA. Isn't this rather large for a watch? What sort of capacity are we
looking at in a watch battery... 25mAh or less? In this case a watch battery
would only last 6 weeks, and that's just powering the oscillator on its own
not even worrying about the watch hands.

73 Hans G0UPL
http://www.HansSummers.com