Nixie Clock ‘SN18’
www.pvelectronics.co.uk
- 16 -
4.14
Seconds LED (D5/SECS on schematic, ‘SECS’ on PCB)
This is a bicolour (red or green) LED. It flashes each second: red if
the clock has no valid WWVB or DCF lock in the last 24 hours, or
green if the clock had a WWVB or DCF lock in the last 24 hours. It
flashes red/green whilst actually receiving a WWVB or DCF frame.
If you are not using the WWVB or DCF synchronisation feature, the
LED will only ever show red, and you may choose to install an
alternative colour LED if you wish, perhaps the orange PM LED if
you didn’t use it in step 4.13 above. In this case refer to Figure 20
below.
Install the bicolour ‘SECS’ LED as follows. It is critical to orient the
LED correctly. It has a long middle lead (-) and two outer leads of
unequal length. Refer to figure 21, which shows the correct
orientation. As with the PM LED, you may use clear insulation on
the leads.
Figure 21: Correct
orientation of the bicolour
seconds indicator LED.
PCB is viewed from the
front.
Figure 20: Correct
orientation of a single
colour seconds indicator
LED. PCB is viewed from
the front.
