K5JXH , Project page and my Journal.                                                       


My new home made CAL Box, my Calibration source box.  (I used this to calibrate some DMM meters and my HP 2430 scope super easy.)  $35? total cost?

10.000000vdc  , LT1236,  chip.   (5mV accuracy and 2PPM/C
10.000000mhz , 7400B2A1 chip, device  1ppm 0 to 50C  (I sync'd it to WWV)
and precision adjustable PSU DPS3003  device below ,voltages from 0 to 34vdc.. 10mV resolution, 0.5% +1 digit accuracy, & digital controls. (imported from CHINA direct, ebay)
I use a 5 digit DDM  to get more accuracy, if need better that 10mV accuracy from the 3003. (my scope needs 0.200v cal point so I use my DDM to attain that)

BOM:
Above 3 devices  and 1 each below.

  • One +36v SMP power pack , CFM25s360 from mouser.com
  • One  uA7805 regulator chip (TO220) and 10v zener  1N4740 1watt, to drop input to 7805  to 26v safely and to  run the 7400B2a1 above at only 5vdc.
  • A Chassis box .
  • 10k resistor for here.
  • 4 banana jacks 4 colors.
  • Power cord and fuse small, say .5amp
  • Power lamp LED, 2v, with drop resistor  to 5vdc reg.  330ohm resistor , org-org-brown
  • PCB bread board,  any kind. Cut to size if needed with a hacksaw.
  • Bus wire and sleeving and hookup wire generic.
36v power runs the DPS3003 device and the LT1236 but  not the 7400B2a1 chip, it needs 5vdc.

Ready to start wiring it up,  power cord and fuse last.



Programmed to 30.00 volts, works great,  It does not drift at all.

Below hot wired hack is just to test for 1 minute,  while fuse holder arrives.







I have always wanted some thing like this , now I have it.
Before this ,I played with voltage divider resistors,  the long hard way to get the voltages I needed, and accurate metal film types. (stable)








v1; 2-20-2018,