+++++++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: "'Gordon Gibson'" , Subject: RE: [Elecraft] K2 Voltage Display Date: Fri, 14 Feb 2003 16:04:34 -0800 If you are comparing it to the voltage measured externally, you have to allow for the voltage drop across the reverse-protection diode in the supply line. That introduces about 0.6v, so I'd say that if you are comparing the display to and external meter, you are in good shape! Ron AC7AC K2 # 1289 -----Original Message----- From: elecraft-admin at mailman.qth.net [mailto:elecraft-admin at mailman.qth.net] On Behalf Of Gordon Gibson The display on my K2 #2746 appears to read .7v low, 73 de Gordon G3ZFZ +++++++++++++++++++++ From: "Bob - AG5Q" To: "Gordon Gibson" , Subject: Re: [Elecraft] K2 Voltage Display Date: Fri, 14 Feb 2003 18:40:25 -0600 Hi Gordon, The voltage that's displayed is the internal 12V line after a series diode (D10 on the RF board). The diode is for protection against reverse voltage. If you measure across a power supply or battery outside the K2, it will be 0.4 to 0.5V higher. This difference in voltage is fairly constant, so if your battery goes down by two volts, the display will track it accurately. The display is probably within about 1-2% and it has 0.1V resolution. The display is an accurate reading of the voltage seen by the circuits in the K2. As long as it stays at or above 10V, you're okay. Below 10V, the audio amp may be affected. Below 9V, the output of the 8V regulator may start to drop. 73/ Bob - AG5Q ----- Original Message ----- From: "Gordon Gibson" To: > How accurate should the voltage display be ? > > The display on my K2 #2746 appears to read .7v low, since my K2 was > completed last August I have only operated it from the shack, and never gave > the voltage display much thought, however I intend to go /p this Spring and > Summer so have been getting ready for that, and charged up my Hitachi 12v > 6.5A battery, it was when I connected to the battery I realised the Battery > Volts were different to the K2 Display, so I checked the voltage of my Drae > Power Supply and it too is reading .7v higher than the K2 Display! > So is the Display only relative ? or do I need to change the values of the > Potential Divider on the control board, i.e. R9, R10 ? in order to get the > display to read my true battery voltage ? > > 73 de Gordon G3ZFZ > > g3zfz at worldonline.co.uk ++++++++++++++++++