What about a switched R-2R Network? or use small realy's, driven by appropriate decade countinglogic to switch individual trimmed resistors.
eric -----Original Message----- From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On Behalf Of lai...@wcoil.com Sent: zaterdag 9 april 2011 9:07 To: neonixie-l@googlegroups.com Cc: lai...@wcoil.com Subject: [neonixie-l] Clock readout based on changing resistance Ohmmeter I know that some of the group have built clock circuits that would output a changing frequency to interface with a Nixie frequency counter. I know that there have been circuits that output current or voltage for analog meters. What I was thinking of was a clock circuit where the output would be a programmable resistance to be read on an ohmmeter. I know there are digital programmable pot ICs. But will any of them output from say 10 ohms to 2400 ohms in 10 ohm steps? I know this could be done with reed relays and discrete resistors set up in a decade circuit. What I was thinking of is I have a couple of very old Wheatstone bridges from the 1800s. You balance the bridge using either numbered rotary decade switches that directly read out the unknown resistance or you use shorting plugs that go into numbered holes to read out the resistance in decades. The bridge is balanced when the galvanometer is nulled out to a zero reading. This would make a unique interactive clock. It wouldn't be very practical but cool. If the switches/plugs were set for a too early or late time(resistance) the galvanometer would read unbalanced. You balance the bridge to read the time. This could also be used on direct reading Ohmmeters as well. I am not sure how much current flows throug th bridge but the old galvanometers are not very sensitive. Tim Laing -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
