Ok...proper testing done..These results may only apply to the examples of the corn-cob style stop/tail bulbsI have (bought over a year ago) and may not be the same as others - but obviously similar to the ones John C has. In these bulbs all of the leds light up in either mode but with different brightness.
Out of interest the tail light mode consume about 0.1 amps each and the stop light mode about 0.25 amps.
When the "stop light" comes on e a voltage appears on the tail light pip about 2 diode drops below the battery voltage.
This "source" has a source impedance of about 33 ohms - ie a short circuit current of about 0.3 amps is available.
Enough to light other led lamps on the tail light group at slightly reduced brightness..May even make an incandescent front side light glow a bit (I didn't try)
No back voltage was output from the brakes light pip when the tail lights were on.
So the effect could be cured ( as John said) by including a small diode (IN4001) in the feed to the "tail lamp" of each"bulb".
Something to be aware of if you buy corn-cob style stop/tail LEDs..Roger
Out of interest the tail light mode consume about 0.1 amps each and the stop light mode about 0.25 amps.
When the "stop light" comes on e a voltage appears on the tail light pip about 2 diode drops below the battery voltage.
This "source" has a source impedance of about 33 ohms - ie a short circuit current of about 0.3 amps is available.
Enough to light other led lamps on the tail light group at slightly reduced brightness..May even make an incandescent front side light glow a bit (I didn't try)
No back voltage was output from the brakes light pip when the tail lights were on.
So the effect could be cured ( as John said) by including a small diode (IN4001) in the feed to the "tail lamp" of each"bulb".
Something to be aware of if you buy corn-cob style stop/tail LEDs..Roger