Hello, I have a circuit to power "stuff" at about 12VDC, but it fluctuates at 150 kHz, and won't really power much because it is oscialtting. So, my question is: How do I turn the 150 kHz to 0, so I can power my projects.
Power Source
- Thread starter robotkid249
- Start date
yourownfree
- Joined Jul 16, 2008
- 99
you must have a switching power supply, the reason for the frequency.
Probably just not big enough to power your project.If you stop it from working "zero" you will have nothing "zero". The only other way I can think of is to hook up a big electrolytic capacitor to it or hook up a voltage regulator then an electrolytic capacitor to smooth it out so there is no hum. It wold be nice as stated to see your diagram or block diagram to see what you are up to.
Probably just not big enough to power your project.If you stop it from working "zero" you will have nothing "zero". The only other way I can think of is to hook up a big electrolytic capacitor to it or hook up a voltage regulator then an electrolytic capacitor to smooth it out so there is no hum. It wold be nice as stated to see your diagram or block diagram to see what you are up to.
jj_alukkas
- Joined Jan 8, 2009
- 753
Add a big cap or a rechargable battery after a diode. The battery need not be working , but will act as a capacitor..
You really do need to post a schematic of your supply.
I suggest that you need a relatively small amount of capacitance at the output of the regulator. A 0.1uF ceramic or poly cap and a 10uF electrolytic cap in parallel should take care of most (if not all) of that 150kHz noise. Both capacitors should have a rating of at least twice your supply voltage, or 2*12 = 24v. Using a really large cap on the output isn't a good idea, as a sudden transient in the circuit being powered will drain the cap, and may result in the power supply being "folded back", or shut down temporarily (reduced current) until the output capacitor is charged back up.
Regulators such as the LM317 and 7812 really do need a small amount of capacitance at the output for good stability. While many regulators may not oscillate, some will under certain conditions.
Lengths of wires does make a difference. If the input wires to your regulator are more than a few inches long, you'll need to add a cap to the regulator across the input to ground, somewhere between 0.1uF and 10uF.
I suggest that you need a relatively small amount of capacitance at the output of the regulator. A 0.1uF ceramic or poly cap and a 10uF electrolytic cap in parallel should take care of most (if not all) of that 150kHz noise. Both capacitors should have a rating of at least twice your supply voltage, or 2*12 = 24v. Using a really large cap on the output isn't a good idea, as a sudden transient in the circuit being powered will drain the cap, and may result in the power supply being "folded back", or shut down temporarily (reduced current) until the output capacitor is charged back up.
Regulators such as the LM317 and 7812 really do need a small amount of capacitance at the output for good stability. While many regulators may not oscillate, some will under certain conditions.
Lengths of wires does make a difference. If the input wires to your regulator are more than a few inches long, you'll need to add a cap to the regulator across the input to ground, somewhere between 0.1uF and 10uF.
