Author Topic: BK Precision 1745A Now working BUT......  (Read 1068 times)

0 Members and 1 Guest are viewing this topic.

Offline BargainhunterTopic starter

  • Regular Contributor
  • *
  • Posts: 116
BK Precision 1745A Now working BUT......
« on: February 06, 2017, 04:49:25 pm »
Many thanks for your help.  I now have my BK 1745 DC Power supply nearly working.  My problem now is that when I try to adjust the voltage below 5 volts the voltage gradually drops to zero unless I add a load across the output posts.  It seems like a capacitor is holding a charge.  Is this normal?  I have attached a schematic for a 1746 which is almost the same (only schematic I could find).

Any input would be greatly appreciated.

Thank you in advance,
Chuck
« Last Edit: February 06, 2017, 04:57:37 pm by Bargainhunter »
 

Offline Kleinstein

  • Super Contributor
  • ***
  • Posts: 14181
  • Country: de
Re: BK Precision 1745A Now working BUT......
« Reply #1 on: February 06, 2017, 05:59:43 pm »
In the shown schematics there are 4.7 K resistors as a minimum load. So the voltage will not go down instantly, but also not that slow. I don't see a reason it should be significant slower below 5 V - just the normal exponential  decay.  Of cause the 1745 might be different (e.g. different resistor values for R1 and R3) at this detail.
 

Offline james_s

  • Super Contributor
  • ***
  • Posts: 21611
  • Country: us
Re: BK Precision 1745A Now working BUT......
« Reply #2 on: February 06, 2017, 06:37:28 pm »
Could it have a dead spot in the adjustment pot?
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf