Jan 3, 2013 #1 S Sharagim Advanced Member level 4 Joined Feb 6, 2011 Messages 112 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,296 Activity points 2,058 Hello, With a typical circuit as datasheet with a IC 7660 I am getting -2.5v between pin 5 and GND is this correct (Vin is +5v)? BR,
Hello, With a typical circuit as datasheet with a IC 7660 I am getting -2.5v between pin 5 and GND is this correct (Vin is +5v)? BR,
Jan 3, 2013 #2 FvM Super Moderator Staff member Joined Jan 22, 2008 Messages 52,485 Helped 14,756 Reputation 29,794 Reaction score 14,121 Trophy points 1,393 Location Bochum, Germany Activity points 298,363 In a (correctly built) typical circuit, 2.5V output would be achieved with about 40 mA load current.
Jan 3, 2013 #3 S Sharagim Advanced Member level 4 Joined Feb 6, 2011 Messages 112 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,296 Activity points 2,058 but isnt it a 5v >>> -5v ? why -2.5?
Jan 3, 2013 #4 K KonstanU Member level 5 Joined Jun 7, 2012 Messages 82 Helped 28 Reputation 56 Reaction score 27 Trophy points 1,298 Location Bayreuth, Germany Activity points 1,719 No. It is very bad result. It means that you have overload. What is your load and what storage capacitors do you use (nominal capacitance)?
No. It is very bad result. It means that you have overload. What is your load and what storage capacitors do you use (nominal capacitance)?
Jan 3, 2013 #5 S Sharagim Advanced Member level 4 Joined Feb 6, 2011 Messages 112 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,296 Activity points 2,058 load is a voltmeter only and I use a 10u capacitor between pin 2 and 4
Jan 3, 2013 #6 K KonstanU Member level 5 Joined Jun 7, 2012 Messages 82 Helped 28 Reputation 56 Reaction score 27 Trophy points 1,298 Location Bayreuth, Germany Activity points 1,719 But, what about capacitance between output and ground?
Jan 3, 2013 #7 S Sharagim Advanced Member level 4 Joined Feb 6, 2011 Messages 112 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,296 Activity points 2,058 Sorry I forget it , when I put it there (10u) now I see -5 10u is ok ? or I should use more?
Jan 3, 2013 #8 K KonstanU Member level 5 Joined Jun 7, 2012 Messages 82 Helped 28 Reputation 56 Reaction score 27 Trophy points 1,298 Location Bayreuth, Germany Activity points 1,719 10u is OK. In your case there is no reasons to try change recommended value because you have very low load (high input impedance of voltmeter).
10u is OK. In your case there is no reasons to try change recommended value because you have very low load (high input impedance of voltmeter).
Jan 4, 2013 #9 S snail888 Member level 1 Joined Dec 15, 2012 Messages 41 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,288 Location china Activity points 1,454 Hi,the exact result should be -5V.And could you post your circuit?