More EDN silliness..

Why not use one ADC and one MDAC?

These mags don't give a hoot about the quality of their "content." It's just filler between the ads, so they can get the post office cheap "magazine" rate ratio.

John

Some are still buying LPs and some are still using tubes for audio reproduction, some are still using telegraphy for radio communication:-).

For the younger generation, which is only used to current digital systems, it might be educational, how things had to be done in the past and appreciate the current solutions.

• Yet another way to KISS.. The work to do that might be too much for them...

and I bought nixies to make a GPS clock....

...

I bought some nixies too, but not sure how to drive them, no application note or circuit for the 7441/74141 -- I have some Russian made nixies and driver chips. Need to see how to make 50V switching work for a ~170V anode?

Grant.

You don't switch the anode- it goes to 170V through a current limiting resistor.

You switch the cathodes, and one is always on for a conventional nixie, so the voltage on the 'off' cathodes can be much lower than

You should be able to find plenty of information on the net for playing with those antiques.

Best regards, Spehro Pefhany

Just run the Nixie tube cathodes to the input pins of the 74141, like in this schematic:

The open-collector outputs of the 74141 have zener diodes across them to protect them against any high voltage transients when the digit is switching on/off. If you're using a microcontroller to drive the IC you only really need one driver IC per clock - just scan the digits by switching their anode voltages with high-voltage PNP transistors.

Why use a mega-integration-scale ROM when a simple multiplying DAC does the job, requires no programming, no chance of metastability or control/clock signal management??? The circuit is a viable chocie for a standalone analog multiplier. I don't consider it to be a novel idea worthy of publication though.

Quarter-square multipliers have the same dynamic range issues as analogue or thermal RMS detectors--when you square the signal, for the same noise floor your N dB dynamic range drops to N/2 dB.

Your average MDAC has enough bandwidth for a 50/60 Hz measurement, but it'll rapidly become inaccurate above that due to excess phase shift.

Cheers

Phil Hobbs

A number of driver circuits used flower power, as in those (old) daze, some of the Geranium transistors had superior BV compared to the sandy ones.

Yep..flower power PNPs.