I have to replace a meter to a piece of analog test equipment in schematic that does not specify what µA range the original was or very much else.
A bunch of resistor dividers, nothing much to see, most ranges have the negative side of the meter to GND, the positive side to the junction of a 2MΩ input resistor and a 120KΩ to GND, "totem pole style". Another one a 5MΩ over a 1MΩ, etc. The only thing it says is about the meter is "range 1 V, input impedance 2 MΩ"
I've never seen the test equipment or the meter, so what did I know. I can tell you it wasn't 50µA. I'm thinking it was somewhere in the 2-5µA range.
To make it worse, it's a center zero type.
The only thing I find at the local shop which is just a local "have it today" shop from China, is a new 50-0-50. The meter barely indicates any signal.
So the question is this ( I'm tired and the answer escapes me, and it's 03:43 and my runtime is 20+ hours ) can the 5µA signal be made larger to the 50µA meter with a simple Op-Amp circuit or other IC that will be a linear translation from the original to the new range?
Where could I find such an example or does someone here know how? The new meter has a DC resistance of 2KΩ.
I wish I could
Age related insomnia..........
Thanks.