Jason Rabel wrote: > What voltage goes to the crystal? I may have had my scope scale too high and > just didn't notice, but at first glance I don't think it was getting power. > > Jason > > > -----Original Message----- > > Yes, the black wires are the thermistor. > > The crystal has three wires. Two are actually connected > to the crystal electrodes. The third is the case. The > case is fastened to the casting with a screw. The only > way the casting gets an electrical ground is by way of the > crystal ground screw and ground wire to the board. > The wires are welded to the crystal, so if you want to > disconnect one of them, you have to unsolder it from the > PC board. > > Rick Karlquist N6RK > > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > Jason
There should be no dc (with respect to ground) on any of the crystal leads. The ac voltage developed across the crystal is determined by the parallel combination of the effective crystal inductance at the operating frequency and the crystal ESR plus the impedance of the trimmer network. Since the crystal current is 1mA rms (see HP journal March 1981 p24) and the crystal ESR is around 50 ohms the AC voltage across R4 in the schematic will only be about 50 mv rms. Bruce _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
