9v battery discharge test
9v battery discharge test
(OP)
Currently, i am making a simple discharge circut to discharge 9 volt batteries at a constant current. Using a resistor won't work because the close circuit voltage will be different depending on the health of the battery. The question is how can i achieve this constant current draw from the battery for the whole lifespan. Is there a simple solution to this? Thanks in advance.
RE: 9v battery discharge test
watch the video, he shows the circuit schematic at about 1:44.
RE: 9v battery discharge test
https://en.wikipedia.org/wiki/Current_source
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RE: 9v battery discharge test
+----res----res-----~
|
Res
|
Ground
RE: 9v battery discharge test
Brad, if you spend a little more, you can use a simpler circuit, see http://www.ti.com/lit/ds/symlink/lm317.pdf figure 14. These have a minimum load current of a few milliamps, but you should be targeting current draws above that level I think?
RE: 9v battery discharge test
The regulator will hold the Voltage between output and reference to 1.2 Volts so all you need to do is calculate the resistor you need to drop 1.2V at the current you want.
e.g. 50 mA 1.2/0.05 = 24 Ohms
RE: 9v battery discharge test
LM316 is an OpAmp.
RE: 9v battery discharge test
Z
RE: 9v battery discharge test
Gunnar Englund
www.gke.org
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