Im trying to make simple laser diode driver from this video
I do everything like on video but i dont get any output voltage on lm317t
(1-12v tested on power supply)
(1-12v tested on power supply)
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Did you measure the voltages on the 3 terminals to see what the regulator was doing? LM317 aren't guaranteed to operate with less than a 10mA load current.I do everything like on video but i dont get any output voltage on lm317t
(1-12v tested on power supply)
No.In the constant current configuration the constant-current-output is from the ADJUSTMENT pin, not the OUTPUT pin.
What size is that resistor? I see orange orange red (3300 ohms) - correct? This means your current will be 1.25v/3300 = some microamps.Yes, black to plus of power supply red to load
so its probably bad resistor? I want to get 150-200 ma
So you're only getting 0.00038 Amps (0.378 milliamperes).
i have one more questionSo you're only getting 0.00038 Amps (0.378 milliamperes).
same answer was given in post #2.
If you are referring to my answer, there are no "Semantics" involved.The datasheets all show the constant current connection point is the adjustment pin. Semantics aside, I will defer to their recommendation.
so its probably bad resistor? I want to get 150-200 ma
Your problem was already pointed out by @panic mode. You're using the wrong resistor value.Yes its 3.3k
It does.I see 0.25 watt and 1 watt resistors
Does it matter in this build?
The problem is that post #4 incorrectly said the output to the LED should come from the output pin – this is incorrect for a constant current regulator.If you are referring to my answer, there are no "Semantics" involved.
I agree the connection point is the Adjustment pin.
But the current comes from the Output pin, not the Adjustment pin.
Okay.The problem is that post #4 incorrectly said the output to the LED should come from the output pin – this is incorrect for a constant current regulator.
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