Page 4 of 10 FirstFirst ... 23456 ... LastLast
Results 31 to 40 of 91

Thread: Jonny reviews lack the Hold Up Time test.

  1. #31
    Join Date
    Jul 2013
    Location
    Chino Hills, CA
    Posts
    282
    Thanks Thanks Given 
    16
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Plated hole board = $5
    LM393 = $0.20
    LM431 = $0.20
    NE555 = $0.10
    1% resistors = <$0.50
    ceramic caps = <$0.50
    electrolytic caps = scavenged from PSUs, $0
    diodes = <$0.50
    relay = $3
    fuse = $0.75
    isolation transformer = scavenged from half bridge PSU, $0
    Add tax and shipping

    Probably less than $25 all up.

  2. #32
    Join Date
    Oct 2006
    Location
    Moderator
    Posts
    6,504
    Thanks Thanks Given 
    149
    Thanks Thanks Received 
    3
    Thanked in
    2 Posts

    Default

    Guys, I am not adding any more time consuming tests.

  3. #33
    Join Date
    Jul 2013
    Location
    Chino Hills, CA
    Posts
    282
    Thanks Thanks Given 
    16
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Ok. I'm going to build it anyway for the Cooler Master lab though, it'll be a useful piece of kit.

  4. #34
    Join Date
    Oct 2006
    Location
    Moderator
    Posts
    6,504
    Thanks Thanks Given 
    149
    Thanks Thanks Received 
    3
    Thanked in
    2 Posts

    Default

    Go right ahead. At this point though anything that increases my workload but does not increase my income is probably not going to happen.

  5. #35
    Join Date
    Jul 2013
    Location
    Chino Hills, CA
    Posts
    282
    Thanks Thanks Given 
    16
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    No problema.

    Travis, I assume you're interested in building one of these as well. Just a heads up, our sense output from the voltage divider will need a voltage follower, since the divider will be relatively high impedance compared to the input of the 393. Not massively so, but enough to be worth buffering.

  6. #36
    Join Date
    Oct 2006
    Location
    jonnyGURU forums, of course!
    Posts
    16,069
    Thanks Thanks Given 
    538
    Thanks Thanks Received 
    274
    Thanked in
    198 Posts

    Default

    hehehe.. I love these forums.

  7. #37
    Join Date
    Jul 2013
    Location
    Chino Hills, CA
    Posts
    282
    Thanks Thanks Given 
    16
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    For the switching device, there are some issues.

    Relay -- Most likely. Medium switching speed. Difficult to isolate. Inexpensive.
    Triac -- Unable to switch off on command. Not usable.
    Mosfet -- Fast switching speed. Easy to isolate, inexpensive. Only blocks in one direction, so needs to follow a bridge rectifier.
    IGBT -- Fast switching speed, not too difficult to isolate, not too expensive. More efficient than mosfets. Only blocks in one direction, so needs to follow a bridge rectifier.
    GTO Thyristor -- Ideal operation, but only available in >1kV and >100A ratings, cost >$200

  8. #38
    Join Date
    Jul 2013
    Location
    Chino Hills, CA
    Posts
    282
    Thanks Thanks Given 
    16
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    Ok, here's my schematic of the HV section. Like I said, isolation is a PITA with relays. But it's doable.

    EDIT: This still isn't quite right.
    Last edited by CM Phaedrus; 03-20-2014 at 08:34 PM.

  9. #39
    Join Date
    Oct 2006
    Location
    Moderator
    Posts
    4,126
    Thanks Thanks Given 
    19
    Thanks Thanks Received 
    14
    Thanked in
    7 Posts

    Default

    And yet, you are still going to need to have the actual equipment to verify that your half baked solution actually works properly, the results are valid, and the results are repeatable.

  10. #40
    Join Date
    Jul 2013
    Location
    Chino Hills, CA
    Posts
    282
    Thanks Thanks Given 
    16
    Thanks Thanks Received 
    1
    Thanked in
    1 Post

    Default

    I can verify it works using a DMM and oscilloscope, which I have, and I can compare vs. our Taipei lab to verify it's consistent. It's not that difficult, nor half baked. And even if it doesn't work I'll get a lot more experience with analog circuitry.

Similar Threads

  1. Replies: 0
    Last Post: 10-27-2017, 03:24 AM
  2. Hold-up time explained
    By -The_Mask- in forum PC Power Supply Discussion
    Replies: 41
    Last Post: 03-19-2017, 01:51 PM
  3. What to do with such screwed hold-up time?
    By Behemot in forum PC Power Supply Discussion
    Replies: 5
    Last Post: 02-12-2017, 12:04 AM
  4. Exploding hold-up time measurement
    By crmaris in forum PC Power Supply Discussion
    Replies: 7
    Last Post: 04-24-2016, 03:47 PM
  5. Why dont you test hold up times in PSU?
    By samer1970 in forum PC Power Supply Discussion
    Replies: 10
    Last Post: 04-18-2016, 10:38 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •