Gents 1 seconds impulse clock and schema


by RODALCO2012

Seconds impulse slave clocks with alternating polarity and current driven.
These clocks were designed for series connection in a current controlled driver circuit with alternating polarity every second.
Drive current may be between 150 and 220 mA.

I got two of these clocks kindly given to me by Electromark1, and posted over from the UK to New Zealand to add to my electric master slave clock collection.
The clocks were used by the BBC as silent clocks in the studio's and now replaced with newer electronic versions.

I designed an simple opto coupler driven circuit which takes pulses of the Gents 1 seconds master clock.
The beauty of opto pulses is that there is no burden on the pendulum, as I have lifted the 1 seconds mechanical contacts, this improves clock accuracy as well.
An aluminium vane was attached to the pendulum and scanned by two opto heads as can be seen in one of my other video's.

I will draw up an exact schema with the LED's in it as well and add a link in the next couple of weeks.

Any questions please post here on YouTube and I will do my best to help to resolve any building issues with the electronic components.

The parts are easily available from any electronics store, the optocouplers may be a bit harder to get. I got mine from some old ferraris disc utility kWh meters which were discarded at our local powerboard.

Parts needed for driver board:
Transistors BC547 or 549 x 6
Transistors BD 139 x 4
Resistors 2k2 Ohms x 4
Resistors 470 Ohms x 2
Resistors 47k or 100k Ohms x 2
Voltage regulator 7812 or LM317 x 1
Capacitors 4700uF 16 or 25 Volts x 2
Supercap 1 Farad 5.5 Volts
LED's optional, some extra series resistors needed ( use 1 k.Ohm for 12 Volts )
Piece of veroboard to fit all parts onto
12 Volts 500mA dc power supply
68 or 82 Ohms 5 Watt ceramic series resistor for clock.