Symbol in IC schematic.

[rqsall]

Hello,

I bought some LM1036 ICs at aliexpress. Fully prepared to take my loss if they turn out to be duds, which they seem to be. However, I would still like to take some measurements and see if I can open a dispute. Now, I'm trying to measure the resistance from the input to ground on it, and I measure open circuit while it should be around 30k, but in the schematic there's a symbol consisting of two circles overlapping partially between the 30k resistor and ground. What does that symbol represent?

The datasheet is here: http://www.ti.com/lit/ds/symlink/lm1036.pdf The schematic is on page 13 and I'm measuring between pin 2 and 10.

Thanks for any input.

[TimFox]

That symbol means a current source:  the schematic simplified that to a basic symbol (probably two or so transistors and some resistors).  With no power applied to the device, that source won't work and the measured DC resistance is not determined.

[rqsall]

Thanks, was just about to answer my own question, because I discovered the 160uA and 220uA values next to some of them. Then googled "current source symbol" and found it.

So I guess I can't determine it this way. Reversing the polarity of the resistance measurement (positive probe on ground pin) gives me 24kOhm and .9V when set to diode. I guess I'm just doing something wrong. 

Thanks again.

[rqsall]

Well, I found out my error. Since I'm lacking some pots, I had just made voltage dividers for the volume, treble, bass and balance controls. "Raising the volume" helped a little.    Also providing a 50ohm resistor to ground at the input to match the 50ohm output impedance of the function generator helped even more. Turns out Mr. Baba sent me working products after all