But Jens is talking about a linear regulateor... eric
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Frank Bemelman Sent: dinsdag 26 juli 2011 0:06 To: [email protected] Subject: Re: [neonixie-l] Nixie Tube Power Supply: 0..300V @ 30mA max. Dissipation is relative small with a pwm driven transistor. ----- Original Message ----- From: "Tidak Ada" <[email protected]> To: <[email protected]> Sent: Monday, July 25, 2011 10:38 PM Subject: RE: [neonixie-l] Nixie Tube Power Supply: 0..300V @ 30mA max. > Hi, > > Did you realize the power dissipation in the transistor? > Better is to use a tranformer with several taps in a circuit like this. > > eric > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of jb-electronics > Sent: maandag 25 juli 2011 19:00 > To: [email protected] > Subject: Re: [neonixie-l] Nixie Tube Power Supply: 0..300V @ 30mA max. > > Hi, > > thanks for the hint. See the reviewed circuit: > > http://www.jb-electronics.de/tmp/400v_adjustable.png > > Yes, the feedback loop will be included, I forgot to mention that my power > supply will have both a volt- and amperemeter built in. > > This way I will be able to check the voltage, as well as to completely > shut > off the PWM stage when the current is too high. Is this safe? > > Does anyone know a good PNP transistor for this purpose? > > Regards, > Jens > > Am 25.07.2011 18:08, schrieb Frank Bemelman: >> I would (at least) add some feedback. Voltage divider and opamp to >> compare against set value. >> Without feedback, the cap would charge to 400V in no time. >> Plus a current limiting resistor of 1K in series with the emitter, >> which makes a lousy protection but still better than nothing. >> >> ----- Original Message ----- From: "jb-electronics" >> <[email protected]> >> To: <[email protected]> >> Sent: Monday, July 25, 2011 5:11 PM >> Subject: Re: [neonixie-l] Nixie Tube Power Supply: 0..300V @ 30mA max. >> >> >>> Hi, >>> >>> thanks a lot for all these replies. I am not an engineer, so I am not >>> familiar with power supply circuitry. >>> >>> These modules on Ebay are nice, but I would like to build my own >>> meters around that supply, that would be a waste of these units I >>> think. They are a tad too powerful for me as well ;-) >>> >>> I like the PWM idea because it is so simple: Why not rectify some AC >>> (after two transformers of course) to say 400V. Then use some suited >>> PNP transistor (which would that be?) that switches the +400V on and >>> off, and then a cap to smoothen the signal. Probably a rather Spartan >>> design yet, any improvements? I can tell it is not protected against >>> shorts. >>> >>> http://www.jb-electronics.de/tmp/400v_adjustable.png >>> >>> The maximum current is then limited by the transformers that are >>> used, isn't it? >>> >>> Thanks again, >>> Jens >>> >>> >>> >>> Am 23.07.2011 02:36, schrieb Charles MacDonald: >>>> On 11-07-22 06:51 AM, Tidak Ada wrote: >>>>> The background is this: I would like to build a universal power >>>>> supply that can be used to drive all kinds of display devices: VFD >>>>> tubes with their 50-60V anode voltage, as well as larger Nixie >>>>> tubes with 300V anode voltage and 25mA current. >>>>> >>>>> >>>>> Any other ideas are quite welcome, too. >>>> >>>> Do you really want to BUILD such an item? They are common on test >>>> benches and with fewer test benches using High Voltage devices, they >>>> are found in surplus. >>>> >>>> I recently got a nice looking unit with 1-400 volts at about 100ma >>>> as a science lab item. Dial the voltage limit, Dial the current >>>> limit. I have not tried it with an audio amp yet, but it should run >>>> fine for Nixie use. >>>> >>>> For example have a look at Ebay >>>> Item number: 230649564649 >>>> Item number: 150634915051 >>>> >>>> >>>> >>>> If you want to look at the OLD school way, My old school test bench >>>> as a Stark Regulated supply, which is one of the schematics at >>>> Pacific TV tubes site. It uses a 6l6 as a pass regulator. The C >>>> supply would cover your VFD requirements. This was surplus from an >>>> Old High School lab. >>>> >>>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "neonixie-l" group. >>> To post to this group, send an email to [email protected]. >>> To unsubscribe from this group, send email to >>> [email protected]. >>> For more options, visit this group at >>> http://groups.google.com/group/neonixie-l?hl=en-GB. >>> >> > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To post to this group, send an email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/neonixie-l?hl=en-GB. > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To post to this group, send an email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/neonixie-l?hl=en-GB. > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
