[time-nuts] SMD TADD-1 distribution amplifier - seeking comments and suggestions?

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Fri Dec 18 03:34:11 EST 2015


On 17 Dec 2015 21:00, "Anders Wallin" <anders.e.e.wallin at gmail.com> wrote:
>
> First prototype assembled today, tested with 12 VDC SMPS wall-wart supply
> and with 12 V lead-acid battery.

> Anders

Is the lead acid battery supposed to be there so the unit continues to
function if power is removed?

If do, I believe that the choice of a lead acid battery is a poor one.  I
believe that even the sealed ones release very small amounts of sulphuric
acid and when contained in equipment the acid results in damage in the
long-term. I believe that people have reported damage to oscillators like
the HP 10811A even on this list.

I believe NiCd would be a better choice.  That said I somewhere read they
were banned in Europe but that might have been for general consumer use, as
I note that they are still shipped in some products - e.g. sone emergency
lights I bought in the UK from Farnell,  although the lights were made in
China. One can certainly still buy NiCd cells in Europe.

I don't know if there is any simple way of slowly charging Lithium Metal
Hydride batteries. Commercial chargers from reputable manufacturers have
temperature sensors, voltage sensors and I assume a microprocessor to
determine how to charge them and when to stop charging.  You don't need to
fast-charge a distribution amplifier,  but I don't know if there's any
relatively simple way of charging them.

Dave.



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