Search found 5 matches

by tetanus
Mon Jan 24, 2005 7:00 pm
Forum: General Discussion
Topic: ground isolation problem
Replies: 12
Views: 2938

Re: ground isolation problem

the meter only needs 1mA and powers up fine with the 1:1 trans and the 7809. I don't know what the impedance and power rating for the trans are but it seems sufficient.
by tetanus
Mon Jan 24, 2005 5:45 pm
Forum: General Discussion
Topic: ground isolation problem
Replies: 12
Views: 2938

Re: ground isolation problem

This is a C + C digital panel meter. 7-12 volt supply. I have changed the surface mount voltage dividers to read in the 0-200V scale. There is not much info out there on these things (which is how I got into this mess). This site has most of the info (almost none) http://shop.store.yahoo.com/webtron...
by tetanus
Mon Jan 24, 2005 5:37 pm
Forum: General Discussion
Topic: ground isolation problem
Replies: 12
Views: 2938

Re: ground isolation problem

yes,the transformer should have done it. There is no physical link between the grounds. What I don't understand is that my commercial benchtop power supply is able to power the meter and read its own output on another channel. The meter also works fine if powered by a 9v battery and meters my homebu...
by tetanus
Mon Jan 24, 2005 9:59 am
Forum: General Discussion
Topic: ground isolation problem
Replies: 12
Views: 2938

ground isolation problem

I am building some adjustable power supplies for my students and have run into a problem with the digital panel meters Im using. After I received them I discovered that they cannot use a common ground to both power the unit (7-12V) and measure the power supply adjustable output (LM317). I then tried...
by tetanus
Wed Dec 19, 2001 4:05 pm
Forum: General Discussion
Topic: DC to DC voltage doubler
Replies: 4
Views: 1898

DC to DC voltage doubler

Im building a counter that is operated by a small 2.4 volt solar panel that will charge up a 1000mfd capacitor and then discharge when a switch is hit to advance the counter. The counter is 4.5 volts so I need to double my voltage before it goes to the cap. This charging of the cap can take a while ...