I'm throwing this in for the guys like me that still have the positive ground 6 volt system. This same setup will work for the positive ground system by using the LM7905 regulator. It is a Negative 5 volt regulator. I am using the NTE961(same thing).
I ran into problems when I no longer could use my King-Seeley type of sensors on my Lincoln Zephyr. In switching to a variable resistance gas sender, oil pressure sensor, etc., I found them to be voltage sensitive. Hence the regulators.
One thing that David or anyone didn't say in how the regulator is mounted to the alum. heat sink. On the 961 the metal screw tab is connected electrically to V(in). So it must be isolated from the alum. heat sink or bad things will happen if one mounts the heat sink to ground. Not sure about the LM7905. I also use a 1 amp blocking diode on the input in case someone hooks the battery or jumper cables wrong. This can easily happen on a positive ground car where both cables are black ( as original).
Last edited by beltfed; 02/05/2014 10:04 PM.
