Low cost Voltage References
              Malone Electronics                     
418 W. Main St. #1542
Battle Ground, WA 98604 USA
email: doug@voltagestandard.com
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The PentaRef provides 5 different DC reference voltages and is an excellent tool for checking the accuracy of your DVM or DMM.  At the time of ordering you specify any 5 voltages (to the nearest 500uV) between 0.10V and 10.0V that suit your needs.  The voltages are sequentially generated, and cycled through, by pressing and releasing the pushbutton adjacent to the LED's shown in the picture, above.  The voltage appearing at the terminals in the lower left corner of the board is guaranteed, at the time of shipping, to be within 250uV of the user specified voltage.  The actual voltage, to the nearest 100uV, will be indicated on the board. 

For example, the above picture shows a PentaRef with the following voltages specified: 1.000V, 1.900V, 2.500V, 5.000V, and 10.000V.  Here is another example:  Lets say one of the five voltages you want is 1.0185V.  You specify that voltage during the PayPal payment process.  At the time of shipment, the voltage is guaranteed to be between 1.01825V and 1.01875V, and the actual voltage will be noted on the board.  After 6 months the voltage will be within the tolerance noted in the specifications summary, below.

All five output voltages are derived from a Linear Technology LT1021BCN8-5 buried Zener reference IC.  To insure long term stability, before shipment each PentaRef is continuously powered-up for a minimum of 250 hours, and then adjusted using our calibrated, 8.5 digit, Keysight 3458A DMM.  The calibration temperature is typically 68 degrees F.

PentaRef recalibration is free for the first two years after purchase - just send it back to us and for USPS Priority return shipping please include $7.00 in stamps or US currency or PayPal payment to doug@voltagestandard.com
After two years the charge is $15.00 plus shipping. Please contact us for shipping charges to destinations outside the USA.

                                                      FEATURE                                                                                                                                       BENEFIT
No adjustments; calibration constants stored in non-volatile memory                     No accidental movement of pots or trimmers
Can be sent back to factory for re-programming with 5 new voltages                     Keeps up to date with changing customer needs

Battery operated
                                                                                                                                                        No ground loop or AC power supply worries
Small size                                                                                                                Easily transported
Short-circuit proof output, and battery reverse polarity protection                           'oops' proof  
Free re-calibration for first 2 years (user pays shipping both ways)                        Low cost of ownership  

Example of Summary sheet that is included with each PentaRef:


Optional Enclosure
The PentaRef optional enclosure (shown above) provides the following:
• Same circuitry and electrical specifications as the standard PentaRef

• Black plastic enclosure surrounds 9V batteries mounted underneath circuit board
• Small rubber feet in bottom corners of enclosure keep unit from sliding on your work surface
• Clear 1/8" thick acrylic cover plate prevents damage if an object is accidentally dropped onto your PentaRef.  Since the cover is clear, the power-on LED, voltage selector push button, and connection terminals are easily seen and accessed.

6 month output voltage accuracy: 
0.100V - 0.999V, 0.2%
1.000V - 1.999V, 0.04%

2.000V - 4.999V, 0.02%

                                                    5.000V - 10.000V, 0.01%
Output voltage temperature coefficient: 6ppm/ºC, typical
Maximum load current: 1mA
Power source: Two 9V alkaline batteries (supplied)
Battery current drain: 5mA
Dimensions (no enclosure):  3" W x 3" L x 1.25" H
Dimensions (with enclosure option): 3" W x 3" L x 2 1/8" H