Electronics Engineering Magazine

Saturday, August 01, 2009

Mixed Circuits Analog with Digital

Mixed Circuits Analog with Digital

Here are some circuits that have both Analog and Digital Signals in them. At one time i wanted to make reed relays, it was a good spot to be in, as it was used in Telecommunications. Even Small Office EPABX systems would have quite a Few of them. It was Simple, get some reeds from OKI and wrap them up in some copper coil and Pot them in a plastic can with epoxy. Before i could get even some trials out, the market was flooded with Good Quality Reed Relays from many.

Fluid or Water Level with Reed Relays


So the Lesson, "Time to Market" should be minimum without sacrificing Quality. That brings us to another metric, The TTM/Q Ratio ;-) . This should not be mixed up with "Time to Exhibition or Trade Show".

Fluid or Water Level with Reed Relays

"Reed Relay. It was invented by Dr. W. B. Ellwood at Bell Labs in 1936. Contacts are in a sealed glass tube filled with inert gas like in a bulb, so they do not corrode. It is faster than regular relays and as no spring is used it has a longer mechanical life. The two contacts are ferromagnetic blades plated with rhodium. When you take a magnet close by, the contacts touch each other. You can also put the reed in a coil, then when you energize the coil the reed operates. Used in telecommunication.OKI is one manufacturer of this type of component. "

Some Circuits on above pages are..
  • Voltage to pulse converter using opamps
  • Analog Section of 8751 based flowmeter
  • Voltage to pulse converter impulse counter
  • 16 channel analog multiplexer
  • 8 channel analog mux with sample hold
  • Digital Control for 8 channel analog mux