Experiments with the LM2575
The standard buck regulator circuit delivers a +5V output. This is a rather straightforward circuit and will operate with a wide spread of component values. Optimal values should be selected however to get minimal ripple, minimal noise to the power source, maximum efficiency etc. Note that the quiesent current is about 10 to 14mA.
Here is a nice way of using this regulator, this can be used for CMOS opamps as you have a -5V too. That means a portable instrument may find this design useful.
The TI Datasheet Layout Guidelines
LM2575 – Step-Down Adjustable Voltage Switching Regulator with Output Enable
The Spirit of Hacking and Fixing, Giving back Life to Old Instruments.
Fluke 8050A LCD display replaced with LED seven-segment
“Recently I was able to cheaply buy a second hand Fluke 8050A made in the early eighties. It is a nice 4.5 desktop digit meter, but a typical problem seems to be that the LCD wears out and goes black. Replacement LCD displays are hard to find, not cheap and probably lead to similar problems in due time.”
