Hello,
I'm just getting started in electronics and I'm trying to build a variable voltage power supply to use while prototyping and testing circuits. It seemed to be pretty straight forward - in fact the datasheet for the LM317 shows the circuit in the typical applications section. So I built the circuit and it works for a little while, but then it seems to stop working. It begins working again when I replace the chip, so I must be damaging it in some way.
I got a 24 volt transformer and rectified it. Output is around 34v DC. C1 is .1uF ceramic, R1 is 330 ohm, R2 is a 6K pot, and C2 is 1000 uF electrolytic.
Any ideas about what could be going wrong? I've even added the protection diodes as shown in figure 3 on page 10 of the data sheet, but I get the same results. I haven't really placed any significant load on the supply. So far, I've only connected LEDs with resistors to test it... The 317 is mounted to an aluminum block heatsink.
-Ranthalion
I'm just getting started in electronics and I'm trying to build a variable voltage power supply to use while prototyping and testing circuits. It seemed to be pretty straight forward - in fact the datasheet for the LM317 shows the circuit in the typical applications section. So I built the circuit and it works for a little while, but then it seems to stop working. It begins working again when I replace the chip, so I must be damaging it in some way.
I got a 24 volt transformer and rectified it. Output is around 34v DC. C1 is .1uF ceramic, R1 is 330 ohm, R2 is a 6K pot, and C2 is 1000 uF electrolytic.
Any ideas about what could be going wrong? I've even added the protection diodes as shown in figure 3 on page 10 of the data sheet, but I get the same results. I haven't really placed any significant load on the supply. So far, I've only connected LEDs with resistors to test it... The 317 is mounted to an aluminum block heatsink.
-Ranthalion
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