Voltage drop of a diode is dependent on the current flowing (according an e-function). If you have the nearly zero current of your tester only, you will get too low figures.
You should test voltage drop with a current similar to that of the driven quartz motor.
However with this adapter and the tiny 357 you lost a lot of capacity / running time. I suspect, this pricey adapter contains nothing more than the schottky diode (<$0.05) that David mentioned above.
EW, you don't supply the 19V to your timer board, do you? Your schematic says 12 V and the 555 is rated at max. 18 V.
A 555 timer is not precise enough to control a clock, unless you want to adjust daily...
No. with the values you posted, current will be even less with 3 V.
A certain swing amplitude needs a certain amount of electric energy.
You can expect longer battery life with 2 pc (3V) than with 1 pc. cell.
The contact, a wire, is visible here:
You should test the coil here:
It will have several 100 ... 2000 Ohms if ok.
The diode is for contact protection against back EMF, the clock will run without diode, too. Tim already mentioned that.
Also test, if there is electrical link between...
imho reasons for no resistor/no spark protection are:
1. low current clocks get not much harm without one. It is not really needed, but with will be better.
2. Manufacturers had no knowledge of electric issues (e.g. Eureka)
I beg to differ.
It applies especially to Eureka type clocks...
the lengthy article in your link tells it all, also points to the disadvantage of diode use.
Ato, Bulle, Brillie have low currents flowing (about 1 mA) and have coreless coils. They store low energy only. Nevertheless I saw >100 Volts back EMF on my Brillie.
Eureka current is 70...
Very good spark protection, contact erosion protection and overvoltage protection is achieved by a resistor 220 … 330 ohms instead of a diode parallel to the coil. This was already known at Eureka inventing times - but not to ist makers :(
Jim, if you prefer to stick to old technology, I wonder...