A quick comparision between the original and the LVR2:

LVR2 Original LVR (LVR1)
3 to 15 volt operation (LVR2)
3 to 36 volt operation (LVR2X)
5 to 8 volt operation, mods for 12 & 18
3.0 to 1 input voltage range with 2% regulation 1.3 to 1 input voltage range with 2 % regulation
Over voltage protection by diming lamp Over voltage caused lamp burn out
Bulb dim up during power on greatly extends bulb life. Same
Auto bulb sensing turns on and off regulator. Seperate switch is only way to turn on and off.
Warning flashing when at end of battery life No warning
Less than 1 milliwatt idle loss (5 volts in) 10 to 50 milliwatts idle loss
Power efficiency above 99% to over 99.8% Power efficiency 97% to over 99%
SMD PCB which is much smaller 0.64 x 1.3 inches
LVR2X PCB 1.4 x 2.65 inches
Printed Circuit Board 1.0 x 1.7 inches

Original Lightbulb Voltage Regulator LVR1

This product was developed in 1993 and the PCB's, kits, and A&T units are no longer available from me but the documentation is useful for those wanting to build or repair an old unit. The documentation is a bit of a mess at the so if you can't find the answer, just Email me willie@cs.indiana.edu.

Documentation for the LVR1

  • Original Caving Newsletter Article
  • Addendum
  • Old Price List and Ordering NOT AVAILALBE ANYMORE! Order the LVR2 or LVR3.
  • Schematic in PostScript
  • PCB layout in PostScript
  • System Wiring in PostScript
  • Read 1st
  • 18 to 12 volts in, 12 volt out modifications
  • 14 to 10 volts in, 6 volt out modifications