Electron Plus
389-1
10V precision battery reference
USER GUIDE
Instructions for use
Battery Operation
Install 2x 9V (alkaline PP3, MN1604, 6LR61). Remove batteries if the unit is not going to be used for
an extended period – discharged alkaline cells will leak and may cause damage to your 389-1.
When switched ON the upper of the two LED’s will illuminate if the batteries combined voltage is
above 15V (2x7.5V). When below this voltage the lower LED will illuminate.
External Power Operation
Connect 12V (minimum) to 15V (maximum) to the device using the supplied lead (white striped core
is +positive). The upper LED will illuminate when the 389-1 is switched ON.
The precision 10V will now be present on the red (positive) and black (negative) 4mm binding posts.
The output voltage will fall slightly if the load exceeds 0.1mA, the maximum current you may draw is
10mA.
The metal enclosure is connected to the green binding post. Typically, you will be connected to the
black (negative) binding post.
Notes
•
Removal of the hologram sticker on the rear of the 389-1, or disassembly of the unit will void
calibration and warranty.
•
The 0V output (black 4mm binding post) and the sleeve of the DC input jack are all the same
potential.
•
The metal enclosure is connected to the green binding post.
•
Best results will be obtained when the unit is at the calibration temperature (usually 20C +/-
1C), powered from a clean 15V DC and allowed to stabilise for at least 15 minutes.
•
The reference is protected against reverse polarity by an internal blocking diode.
•
Internally the device has diodes between the output of the battery and the output of the
internal DC/DC converter, so no damage will occur if the batteries are left in the unit when
externally powered.
•
For lowest noise, use the battery powered operation (due to the small amount of noise
created by the internal DC/DC converter when powered by an external source)
•
No damage will occur if the outputs are shorted together, however, the output voltage will
need several minutes to settle when the short is removed (due to internal heating of the
reference IC).
Electrical & connections
Input: 12V to 15V, DC @ 30mA (maximum)
Connector: 2.1mm ve barrel jack socket, supplied with 1.8M DC lead (bare tails)
Output: 10V +/- 0.003% at maximum load of 0.1mA (100Kohm load) @ 20C +/- 1C
Maximum Load: 10mA
Temp Coeff: 2.5ppm per °C
Operating: 5-80% RH, 10-40°C*, sea level to 2KM
Connector(s): 3x 4mm binding posts (RED, BLACK and GREEN)
*calibration is only guaranteed at 20C+/-1C
Physical