What is the voltage you expect out of the high voltage unit and how much current? As has been suggested a current transformer is the way to go as they come in different current ratings and will out put a voltage proportional to the current. A wire is passed through the toroidal section of the transformer and the windings are designed to give a current or voltage out at the designed value - usually 5A or 5v depending on its design. You can also get 4 to 20ma loop transformers if that is what you want - let me know what you are measuring and I will see if I can find a suitable supplier for you. Are you using a PIC i.e. you want 5v maximum level? ************************************************* Roy Hopkins :-) Tauranga New Zealand ************************************************* ----- Original Message ----- From: "Roberts II, Charles K." To: Sent: Saturday, March 13, 2004 9:33 AM Subject: Re: ] Measuring Current in a High Voltage Circuit The Circuit I was talking about in my orginal post. Charles K Roberts II -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Roberts II, Charles K. Sent: Friday, March 12, 2004 3:29 PM To: PICLIST@MITVMA.MIT.EDU Subject: [EE:] Measuring Current in a High Voltage Circuit Hello All I am working on a PIC based High Voltage module. The schematic of the current meter portion of the module is attached. I am measuring the voltage drop across a knowm resistor, but to do it I had to use two voltage dividers to bring the levels to something I can read. I measure about the same current with or without a load. What could be going on? Loooking into the devider there are 50Meg Ohms to Ground, Is this what is messing up my reading? Thanks in Advance Chuck Roberts -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.617 / Virus Database: 396 - Release Date: 9/03/2004 -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads