He also said larger resistors did not work, which is obviously nonsense IF it was connected correctly, which I doubt.

Bob

 

He also said larger resistors did not work, which is obviously nonsense IF it was connected correctly, which I doubt.

Bob

I tried the voltage divider with a 4k and a 1K, AND the 2N3904 transistor. Both gives me good results at 1kHz.

 

this is the best solution for me, The resistor divider works but with low ohmic values not in the K ohm values. I was down to 2ohm with 10 ohm resistors, But I needed a Pot and as soon as I introduce that in the circuit, then the output was unstable. The 2N3904 is a low cost transistor anyway. thank you

That is because the load is drawing more current through the 2-resistor divider then you think it is. So you needed a buffer to isolate the divider from the load, a buffer with enough drive capacity to provide enough drive current for the load..

Probably could have done the same thing with a non-inverting opamp buffer instead of BJT.

 

That is because the load is drawing more current through the 2-resistor divider then you think it is. So you needed a buffer to isolate the divider from the load, a buffer with enough drive capacity to provide enough drive current for the load..

Probably could have done the same thing with a non-inverting opamp buffer instead of BJT.

I tried the BJT at 1Mhz, and its coming very hot ! so that wont be a solution. I guess resistor divider with OPamp.

 

I tried the BJT at 1Mhz, and its coming very hot ! so that wont be a solution. I guess resistor divider with OPamp.

Show us a schematic of your circuit

 

A 5kΩ load draws 1mA from a 5V source.
The AD835 takes 10μA.
Why do you need an opamp?

 

A 5kΩ load draws 1mA from a 5V source.
The AD835 takes 10μA.
Why do you need an opamp?

Sorry I dont need OPAMP, just voltage divider.

I am using OPamp after the AD835, but thats irrelevant here.

I dont know why the voltage divider didnt work work before when I tried it.

case closed, thanks everyone.

 

Well that explains everything starting at post #1.

 

Plugged the wires into the wrong holes on the breadboard?

Bob

 

Plugged the wires into the wrong holes on the breadboard?

Bob

who knows, cant go back in time.