Hello, I installed that Chinese regulator and cannot get lower enough voltages. The seller don't understand because of the language barrier. It says in the add that it reaches -12 to -25 V, however I turned the trimpot and it doesn't get lower than -13.5V , I only want -12.5V max, my DC is -24V which I cannot lower.
First off, I hope you didn't pay $20 for a single regulator.... They're normally about $2.50....
Secondly, please be clear here, did you buy an LT337, or an LM7912? If its the 7912, as pinholer suggests, what do you measure, with no R1 or R2, and the regulator pin 1 tied directly to ground?
Secondly, please be clear here, did you buy an LT337, or an LM7912? If its the 7912, as pinholer suggests, what do you measure, with no R1 or R2, and the regulator pin 1 tied directly to ground?
The LM7912 is not intended as an adjustable regulator, but if its ground pin is grounded, the input is connected to -15 V or below, it should have no trouble delivering -12 V. So the circuit shown with the trimpot shorted and R1 plucked should work.
Tom
Tom
Tom, thanks, I should but it doesn't, it's a regulator with some pnp outputs, it has a trimpot, just out of range, it's a sochi tech lol
Did you connect and measure it with a minimum load of sorts?
As a master in chinglish (plus dealing with native speakers) I think some translations and meanings are not easy to understand. The regulator can be used for both LM337 and 79xx pinout (which are the same contrary to 78xx/LM317) and it is hinted to look carefully to the pinout. The LW79xx (its name!) has GND - Vin - Vout pinout and can be used in 79xx/LM337 situations but in LM337 situations R1 should be removed and a jumper for R2 should be installed. Apparently it has setting resistors onboard.
Those in the link you gave are not the same as these are non adjustable.
As a master in chinglish (plus dealing with native speakers) I think some translations and meanings are not easy to understand. The regulator can be used for both LM337 and 79xx pinout (which are the same contrary to 78xx/LM317) and it is hinted to look carefully to the pinout. The LW79xx (its name!) has GND - Vin - Vout pinout and can be used in 79xx/LM337 situations but in LM337 situations R1 should be removed and a jumper for R2 should be installed. Apparently it has setting resistors onboard.
Those in the link you gave are not the same as these are non adjustable.
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