[Amps] Led display problem

[Tony King - W4ZT]

If you really like the LED bar meters you should take a look at Paul
Hewitt's display at <http://home.earthlink.net/%7Ewd7s/ds-1.htm>.

73, Tony W4ZT


David Kirkby wrote:
> Patrick EGLOFF wrote:
> 
>>Hi All,
>>I'm new on this list...
>>
>>I'm planning to build a 2m amp with a 4CX1500B tetrode.
>>I want it a bit state of the art and replace the meters with LED bars.
>>
>>My design will be a cathode driven, DC grounded amplifier and i want to 
>>monitor at least screen, grid and anode current and anode voltage.
>>
>>The LM3914 input seems to be always referenced to ground. No problem to 
>>measure the screen current for which a pole of the supply is grounded.
>>
>>But a bit more difficult to measure the other currents and voltages for 
>>which the reference et the cathode level.
>>
>>Has anyone an idea how to do that, on a simple way ?
>>
>>73, Patrick TK5EP.
>>http://tk5ep.free.fr
> 
> 
> Personally I don't think bargraphs are as useful as analogue meters, 
> but, if that is what you want, there are  few options.
> 
> 1) You can easily use a small transformer to power the circuit. Rectify 
> the secondary voltage and reference that where you want (within reason). 
> The secondrary will not mind being at what voltage it is connected to 
> with respect to the chassis (within reason). I'd not do it in the high 
> voltage side of the anode though!!
> 
> 2) Even easier, if you can find some surplus, small DC-DC converters. 
> Again, these are often isolated to 1 kV or so. New they tend to be quite 
> expensive.
>