Hi Guys,
First post here. Excuse my English, not my native language.
Hi Dave,
In the user manual for DP832 Rigol has a TIP:
When powering on the Instrument after powering off it, make sure that the time interval between the two operations is greater than 5s.
Would it be possible for you to make another test and see if that spike is still there after 5s?
Thanks for the great reviews and info.
The question I have for anyone is Dave did a start up transient with the output enable (not the power switch) and said it did not over shoot. If I'm not mistaken it was done at higher voltages. Can anyone that has one of these confirm that they do not over shoot at lower voltages such as 1.2V, 1.8V, 3.3V 2.5V... I have a POS bk precision 1550 and it overshoots and their response is basically it is a crappy supply and to but a better one... WTF! Dont sell it if you all know it is a POS!
Having watched Dave's video I measured my tti ql355 power supply for switch on spikes, and was amazed to see 4 or 5 transients up to 20v, positive and negative, though only for about 100ns duration per transient.
...
Central to all of this is the question: Can a DC power supply output be expected to never leak DC when the AC power is turned on while the outputs are turned off? Does anyone have such a power supply?
Having watched Dave's video I measured my tti ql355 power supply for switch on spikes, and was amazed to see 4 or 5 transients up to 20v, positive and negative, though only for about 100ns duration per transient.
Wow, TTi has been one of my holy grails / hopefuls on this issue, are you pretty sure? (I'm sure you are sure, just checking )
Maybe we need a bit of written / clear-cut test protocol so that we are all looking at / testing the same things?
Once we get a simple test process then we could see if users of various PSs (Rigol, TTi, Agilent, and others) might be up for following the script and reporting the results.
Central to all of this is the question: Can a DC power supply output be expected to never leak DC when the AC power is turned on while the outputs are turned off? Does anyone have such a power supply?
Having watched Dave's video I measured my tti ql355 power supply for switch on spikes, and was amazed to see 4 or 5 transients up to 20v, positive and negative, though only for about 100ns duration per transient.
Wow, TTi has been one of my holy grails / hopefuls on this issue, are you pretty sure? (I'm sure you are sure, just checking )
Maybe we need a bit of written / clear-cut test protocol so that we are all looking at / testing the same things?
Once we get a simple test process then we could see if users of various PSs (Rigol, TTi, Agilent, and others) might be up for following the script and reporting the results.
Most likely it is simply the spark produced by the switch creating a wideband RF noise source, your circuit will not see that, but a high impedance scope input will.
A stupid question
What do you use such a power supply for? I am wondering what sort of projects are you working on.... Same for the your 20Mhz+ oscillos.
I seem to be happy with my USB scope, batteries and sometimes my PC power supply, I want to know what am I missing out for being such a cheap ass
Cheers!
Central to all of this is the question: Can a DC power supply output be expected to never leak DC when the AC power is turned on while the outputs are turned off? Does anyone have such a power supply?
The easy way would be to put a real relay in the output on/off switch, when you depend on solid state stuff there is always the uncertaincy when you power it up.
Central to all of this is the question: Can a DC power supply output be expected to never leak DC when the AC power is turned on while the outputs are turned off? Does anyone have such a power supply?
The easy way would be to put a real relay in the output on/off switch, when you depend on solid state stuff there is always the uncertaincy when you power it up.Yep, I agree with PA0PBZ: consider a relay or FET that isolates the outputs just long enough for stable operation at 0.000 volts (perhaps use a low cost power monitoring chip for that purpose), then turn on the outputs, thus blocking any output instabilities. Then, if this option was selected for power on, let the unit do it's normal clean ramp to the remembered output settings.
Another poster posited (using other words) that perhaps this capability is there and just not working in firmware... could be an easy fix then.
Central to all of this is the question: Can a DC power supply output be expected to never leak DC when the AC power is turned on while the outputs are turned off? Does anyone have such a power supply?
The easy way would be to put a real relay in the output on/off switch, when you depend on solid state stuff there is always the uncertaincy when you power it up.Yep, I agree with PA0PBZ: consider a relay or FET that isolates the outputs just long enough for stable operation at 0.000 volts (perhaps use a low cost power monitoring chip for that purpose), then turn on the outputs, thus blocking any output instabilities. Then, if this option was selected for power on, let the unit do it's normal clean ramp to the remembered output settings.
Another poster posited (using other words) that perhaps this capability is there and just not working in firmware... could be an easy fix then.
Pretty sure this won't be fixed in firmware as the output glitch it likely caused by an unknown state before the onboard micro-controller has finished loading/booting/setup etc.
I think some engineers and technicians get way too caught up in the test equipment on the bench and lose sight of what the hobby/profession is all about and the Rigol 832 is a perfect example of this.
Depending on how well they write the boot loader they can still minimize it. If they make sure that the very first instructions the MCU fetch on power on reset sets the GPIO pins to shut the FETs off they have a shot at cutting the pulse down to micro seconds.
Would I trust a 832 to Bias a $300 RF FET, No Way!
Would I trust a 832 to Bias a $300 RF FET, No Way!
Well but this is an extreme example and not really representative of what people around here work on.. Also raising the voltage to 6V as ElectroIrradiator is not a good case since there are many simple ways to do it (add one battery?)
I'm looking for examples that would justify buying these scopes and power supplies, and you guys are perfect for that since you may be fully utilizing such equipment.. Could you guys give any examples?
I'd like to list 10 reasons/projects where I'd need such lab equipment (rather than a PC power supply unit)
Cheers
Depending on how well they write the boot loader they can still minimize it. If they make sure that the very first instructions the MCU fetch on power on reset sets the GPIO pins to shut the FETs off they have a shot at cutting the pulse down to micro seconds.
With your PC power supply how do you set the voltage for 3.3 volts and 0.25 amps? And then what do you have to do to set it to 5.0 volts and 1.0 amp? Or 20.5 volts and 4.5 amps?