Tech Forum Questions

According to the information about tne DG10A tube, it isn't a Nixie tube (which uses cold cathode shaped numbers that illuminate orange under a high voltage in the neon gas inside the tube), but a fluorescent glow tube, which uses a multi-segment cathode coated to glow green-blue under a high voltage, like the Nixie. This type of display was used in medium sized calculators and some digital clocks because the emitted light can be filtered, and a version with many digits using a multiplexed circuit was later used in calculators until the LED and LCD displays replaced them I still see calculators with these fluorescent displays. on many desks.

I found an eBay offer for the same type of tube (item #251596633619) that sells the tubes but has posted the wiring diagram for it. Look at the item diagrams to wire up the tube and test it.

The DG10A is not a nixie tube but is a 7 segment vacuum fluorescent tube. This vacuum fluorescent readout operates much in the fashion of a triode vacuum tube. A heated filament/cathode emits electrons that are attracted to any of the 7 anodes which are biased with a positive voltage. Each anode is coated with a material that fluoresces when the electrons strike the anode. Changing biasing on the control grid varies the intensity of the electron flow and therefore the brightness of the display. The filament requires about 50 milliamperes, which operates just below its incandescent level. About 0.8 VDC will provide the required current. Apply about 50 VDC to each anode (segment) that you want to turn on. For test purposes, the common control grid may also be biased at 50 VDC to provide maximum brightness. The pin-out for the DG10A may be found at www.radiomuseum.org/tubes/tube_dg10a.html

Attached is a zip file containing two files in response to Don Franklin’s question regarding a Quick Basic Program he wanted to develop. The code is “Very Well” documented with comments and should not require any additional explanation.

Listing_2.zip

'**************************************************************************
'*                     PROGRAM DESCRIPTION                               *
'**************************************************************************
'Program asks for the PATHNAME of the DATAFILE.
'   1.  The PATHNAME can have any name that conforms to the 8+3 character
'       limit of the earlier versions of DOS.
'   2.  The Default PATHNAME is "C:\QB\DATAFILE.TXT"
'   3.  The Datafile can have any number of Records but, they must conform                                                
'       to the following Spec.
'    
'       "mm/dd/yyyy", "nn, nn, nn, nn, nn, nn", "(nEVEN/nOdd)" cr-lf
'       | 12 chars |2 |      19 Chars        | 2|  14 Chars  |  2  |
'
'       for a total of 51 characters per record.
'
'The program opens the DATAFILE, determines how many records it contains
'   and loads them into an array of special TYPE "Records"
'While loading the data, the order of elements in the DATE are re-arranged
'       mm/dd/yyyy to yyyy/mm/dd
'
'The program then asks the user to input a 1, 2 or 3 as defined below.
'
'   (1) SORT IN ASCENDING ORDER: ALL ACTUAL NUMBERS DRAWN
'       (and the corresponding 'dates drawn')
'   (2) SORT IN ASCENDING ORDER: DATES DRAWN
'       (and the corresponding 'numbers drawn')+
'   (3) EXIT PROGRAM
'
'The program then prints 20 Data Records at a time waiting for the user
'   to hit any key to move on the the next screen.
'
' AllData()N = DATE DRAWN
' AllData()B = ACTUAL NUMBERS DRAWN
' AllData()C = RATIO OF EVEN/ODD NUMBERS CONTAINED
'
' Edited by Raymond Perry
' [email protected]
'**************************************************************************
'
'**************************************************************************
'*        DESCRIBE a MULTI DIMENSIONAL ARRAY TO HOLD THE DATA             *
'**************************************************************************
'
TYPE Records
    N AS STRING * 12
    Spcr1 AS STRING * 2
    B AS STRING * 19
    Spcr2 AS STRING * 2
    C AS STRING * 14
    CRLF AS STRING * 2
END TYPE
'
'**************************************************************************
'*        Designate the AllData() array to be re-dimensionable            *
'**************************************************************************
'
'$DYNAMIC AllData() AS Records
'
'**************************************************************************
'*               [DIMENSION other variables]                              *
'**************************************************************************
'
DEFINT A-Z
DIM IK AS STRING, TEMP  AS STRING
DIM Pathname AS STRING
'
'**************************************************************************
'*                     PROGRAM STARTS HERE                                *
'**************************************************************************
'
CLS
'
'**************************************************************************
'*                     PROGRAM STARTS HERE                                *
'**************************************************************************
'
'
'**************************************************************************
'*            Get the FileSpec of the File containing the DATA            *
'**************************************************************************
'
PRINT "Enter the complete PATHNAME of the file containing the data."
PRINT "EXAMPLE: C:\QB\DATAFILE.TXT"
INPUT Pathname
'
'**************************************************************************
'*            Use Default FileSpec if input is null                       *
'**************************************************************************
'
IF Pathname = "" THEN
    Pathname = "C:\qb\datafile.txt"
END IF
'
'**************************************************************************
'*            OPEN the File containing the DATA                           *
'*            BINARY access simplifies GETTING DATA                       *
'**************************************************************************
'
OPEN Pathname FOR BINARY AS #1
'
'**************************************************************************
'*            There are 51 characters in each record                      *
'*            There are K Records in the DATA FILE                        *
'**************************************************************************
'
K = LOF(1) / 51
'
'**************************************************************************
'*         REDIMENSION AllData() Array to make room for K elements.       *
'**************************************************************************
'
REDIM AllData(K) AS Records
'
'**************************************************************************
'*         GET the DATA RECORDS and hold them in the AllData(K) array     *
'*         Re-arrange the .N element to YYYY\MM\DD                        *
'**************************************************************************
'
FOR I = 1 TO K
    GET #1, , AllData(I)
    TEMP = CHR$(34) + MID$(AllData(I).N, 8, 4) + "/"
    AllData(I).N = TEMP + MID$(AllData(I).N, 2, 5) + CHR$(34)
NEXT
'
'**************************************************************************
'*         GET the User input to determine sort method or exit prog       *
'*         This is a "DO Forever" loop until the user enters "3" to exit  *
'**************************************************************************
'
DO
    CLS
    PRINT "Enter 1 to sort by NUMBER."
    PRINT "Enter 2 to sort by DATE."
    PRINT "Enter 3 to EXIT the program"
    IK = ""
    '**** Loop Here until user Enters 1, 2 or 3  **************************
    DO WHILE (IK <> "1") AND (IK <> "2") AND (IK <> "3")
        IK = ""
        IK = INKEY$
    LOOP
'
    IF IK = "3" THEN END
'
'**************************************************************************
'*         Continue if user entered a 1 or a 2                            *
'*         Swapping AllData(J) keeps all elements together                *
'**************************************************************************
'
    IF IK = "1" THEN ' SORT BASED ON NUMBERS DRAWN
        FOR I = 1 TO K - 1
            FOR J = 1 TO K - I
                IF AllData(J).B > AllData(J + 1).B THEN
                    SWAP AllData(J), AllData(J + 1)
                END IF
            NEXT J
        NEXT I
    ELSE        ' SORT BASED ON DATE
        FOR I = 1 TO K - 1
            FOR J = 1 TO K - I
                IF AllData(J).N > AllData(J + 1).N THEN
                    SWAP AllData(J), AllData(J + 1)
                END IF
            NEXT J
        NEXT I
    END IF
'
'**************************************************************************
'*         It is time to Print                                            *
'*         Swapping AllData(J) keeps all elements together                *
'**************************************************************************
'
' *********************[ TIME TO PRINT 20 lines ]**************************
    CLS
    FOR Z = 0 TO INT(K / 20) 'THIS CAUSES MULTIPLE PAGES TO PRINT
        FOR I = 1 TO 20  ' THIS LIMITS TO 20 ITEMS PER SCREEN
            IF (Z * 20 + I) <= K THEN
                Y = I + Z * 20
                PRINT Y, AllData(Y).N; AllData(Y).Spcr1; AllData(Y).B;
                PRINT AllData(Y).Spcr2; AllData(Y).C ' ALLDATA(Y).CRLF;
            ELSE
                EXIT FOR
            END IF
        NEXT I
' ***************[ BREAK AT 20 AND WAIT FOR ANY KEY ]************
        PRINT
        PRINT "PRESS ANY KEY TO PRINT THE NEXT SCREEN."
        IK$ = ""
        DO WHILE IK$ = ""
            IK$ = INKEY$
        LOOP
        CLS
    NEXT
LOOP
'
END

DATAFILE.TXT

"10/22/1994", "10,16,20,28,39,40", "(5Even/1Odd)"
"12/10/1994", "21,23,35,37,39,48", "(1Even/5Odd)"
"01/07/1995", "24,31,33,35,40,44", "(3Even/3Odd)"
"02/04/1995", "11,20,21,24,29,42", "(3Even/3Odd)"
"02/11/1995", "14,17,25,30,31,34", "(3Even/3Odd)"
"05/06/1995", "15,18,23,24,36,48", "(4Even/2Odd)"
"05/20/1995", "11,27,34,35,37,45", "(2Even/4Odd)"
"06/25/2003", "10,16,31,35,38,43", "(3Even/3Odd)"
"06/28/2003", "18,19,26,34,46,47", "(4Even/2Odd)"
"07/02/2003", "20,25,26,36,37,47", "(3Even/3Odd)"
"07/16/2003", "10,16,22,24,26,37", "(5Even/1Odd)"
"08/23/2003", "17,24,26,28,41,44", "(4Even/2Odd)"
"06/25/2004", "11,16,31,35,38,43", "(3Even/3Odd)"
"06/28/2004", "12,19,26,34,46,47", "(4Even/2Odd)"
"07/02/2004", "24,25,26,36,37,47", "(3Even/3Odd)"
"07/16/2004", "15,16,22,24,26,37", "(5Even/1Odd)"
"08/23/2004", "17,24,26,28,41,44", "(4Even/2Odd)"
"06/25/2005", "15,16,31,35,38,43", "(3Even/3Odd)"
"06/28/2005", "12,19,26,34,46,47", "(4Even/2Odd)"
"07/02/2005", "24,25,26,36,37,47", "(3Even/3Odd)"
"07/16/2005", "14,16,22,24,26,37", "(5Even/1Odd)"
"08/23/2005", "20,24,26,28,41,44", "(4Even/2Odd)"
"06/25/2006", "15,16,31,35,38,43", "(3Even/3Odd)"
"06/28/2006", "12,19,26,34,46,47", "(4Even/2Odd)"
"07/02/2007", "24,25,26,36,37,47", "(3Even/3Odd)"
"07/16/2007", "14,16,22,24,26,37", "(5Even/1Odd)"
"08/23/2008", "20,24,26,28,41,44", "(4Even/2Odd)"
"10/22/1994", "10,16,20,28,39,40", "(5Even/1Odd)"
"12/10/1994", "21,23,35,37,39,48", "(1Even/5Odd)"
"01/07/1995", "24,31,33,35,40,44", "(3Even/3Odd)"
"02/04/1995", "11,20,21,24,29,42", "(3Even/3Odd)"
"02/11/1995", "14,17,25,30,31,34", "(3Even/3Odd)"
"05/06/1995", "15,18,23,24,36,48", "(4Even/2Odd)"
"05/20/1995", "11,27,34,35,37,45", "(2Even/4Odd)"
"06/25/2003", "10,16,31,35,38,43", "(3Even/3Odd)"
"06/28/2003", "18,19,26,34,46,47", "(4Even/2Odd)"
"07/02/2003", "20,25,26,36,37,47", "(3Even/3Odd)"
"07/16/2003", "10,16,22,24,26,37", "(5Even/1Odd)"
"08/23/2003", "17,24,26,28,41,44", "(4Even/2Odd)"
"06/25/2004", "11,16,31,35,38,43", "(3Even/3Odd)"
"06/28/2004", "12,19,26,34,46,47", "(4Even/2Odd)"
"07/02/2004", "24,25,26,36,37,47", "(3Even/3Odd)"
"07/16/2004", "15,16,22,24,26,37", "(5Even/1Odd)"
"08/23/2004", "17,24,26,28,41,44", "(4Even/2Odd)"
"06/25/2005", "15,16,31,35,38,43", "(3Even/3Odd)"
"06/28/2005", "12,19,26,34,46,47", "(4Even/2Odd)"
"07/02/2005", "24,25,26,36,37,47", "(3Even/3Odd)"
"07/16/2005", "14,16,22,24,26,37", "(5Even/1Odd)"
"08/23/2005", "20,24,26,28,41,44", "(4Even/2Odd)"
"06/25/2006", "15,16,31,35,38,43", "(3Even/3Odd)"
"06/28/2006", "12,19,26,34,46,47", "(4Even/2Odd)"
"07/02/2007", "24,25,26,36,37,47", "(3Even/3Odd)"
"07/16/2007", "14,16,22,24,26,37", "(5Even/1Odd)"
"08/23/2008", "20,24,26,28,41,44", "(4Even/2Odd)"

I don't have a quick answer for you, but the version of QuickBASIC you are using is quite out of date. Of the BASICs running on micros these days, I don't think any still use line numbers, REM statements and the like. The language is more structured with subroutine and function names. I too cut my teeth on HP educational BASIC from that era, but really don't miss RENUM as a edit feature. Now you compose programs in an editor and download them to a target. Our BASIC which targets various ARM processors can also be run on a PC in emulation mode, so you can start out writing programs there. www.coridium.us/files/setupBASIC.exe

Don, I'm not a QuickBASIC user, but what I see is you need matching SWAP statements (just like you say) in 290 & 347 when true, SWAP N$, SWAP B$, SWAP C$ then your arrays should stay in sync.

I'm not sure I follow your screen print requirement, however, the INPUT statement should allow you to both print an output and then wait for the Enter key to be pressed before continuing. Place the statement at the point you want to interupt. One more thing, the loop 330-339 will print the same value for D$ over and over, you want to move 311 to 331.

My suggestion would be to put an LM7812ACT linear three-pin regulator (about $0.69 each, plus shipping, from Digi-Key.com) between the solar panel and each fan. Be SURE to read the spec sheet carefully and use bypass capacitors on BOTH the input and output. (Guess how I know to warn about that!) You'll also need some sort of heat sink on each, though some scrap of aluminum should suffice -- my guess would be four square inches or more should do the trick. (If necessary, cut up an empty aluminum can, though fold the edges over to avoid sharp edge hazards.)

Using a "low dropout" regulator would mean more efficiency, but at a noticeably higher cost.

P.S.  I notice that you're in San Diego.  You can probably get the parts at Fry's Electronics, though for a little bit higher cost. The spec sheet can still be had at Digi-Key.com. (Wish Fry's would provide scooters for their mobility-limited customers!)

It’s not likely that the voltage from the solar collector, under load, will be enough to damage the fans. However, to be safe, you could put a 13 volt, 15 watt zener across the collector output. The fans will be drawing 1.53 amps while the collector is trying (best case) to put out 2.5 amps, so the zener will have to sink 0.97 amps. I could not find such a zener in the Mouser catalog, so the alternative is to use a power transistor amplifier, see diagram (the part numbers are Mouser).

The zener current is just the base current, about 33 mA. It is DO-41 (1 watt) and costs 22 cents. The transistor sinks 0.97 amps and dissipates 13 watts.  It costs 99 cents. A heat sink will be needed; Mouser part number 588-FA-T220-51E is suitable and costs $1.56. The heat sink is mounted vertical. It has two 0.091 solderable posts, diameter spaced one inch.

A good solution to this issue is to use a switching regulator. It has very high efficiency, close to 90%, and will take the 20+ VDC from your panel and even increase the current output some!! Go to "sul-tech" on YouTube, and you will find the solar optimizer schematic....hope it helps.

The 30W rating on your solar panel is very optimistic and requires a LOT of direct sunlight to reach that rating. You might need more than one panel to do what you want to do. I think you will find that you have the opposite problem of what you are concerned about. Solar panels have a very large output impedance, which means that the voltage will drop to a low value when you connect a load like an electric motor that has a low input impedance.

Also note that electric motors are rated at their RUNNING power requirements and they need much more current to START. You will need a buck-boost voltage regulator to do what you need to do. It raises the voltage when the light is dim and lowers the voltage when the light is bright.

Since your motors will require more than one amp you will need to find a regulator that is capable of supplying at least 2 amps and I recommend one rated at 3 amps or more.

Your solar panels only show that high of voltage when they are unloaded. Once you put the fans on them, the voltage will adjust to their rated voltage, providing you have enough sun light to drive them properly.

The other good news is that the fans will not burn up when more voltage is applied to them. They will run faster and wear out sooner, but to fry them, you would need much more than a single solar panel can produce.

The solar panel you have says 30 watts, but what they actually mean, is that under ideal conditions, it can produce 30 watts. Two panels would assure that the fan would run in less than ideal sun light.

I would use a simple LM7812 voltage regulator for each fan. The 7812 can take up to 18V in and as low as 5V and has a current rating of 1 amp. Based on your specs, you will only be drawing a little over half an amp on the 7.6 W fan and a little under a half amp on the smaller fans.  If you find that they get hot, you can easily add a heat sink.

I will also mention that I did something similar, running a boom box radio at the beach, and found that unless the panel is pointed at the sun constantly, the output will drift when fair weather clouds cross overhead. So, I connected 3 1000000 20V caps in series, which slowed down the drifting effect caused by clouds.

Another option is to use a solar charger controller like the one I picked up at harbor freight tools. You would hook up the solar panel to the controller, then the controller to the battery (car/marine), and run the fans off the battery. I would still use the LM7812 voltage regulator just to protect the fans.

I want to offer some facts that may help you form your own solution.

  1 - 7.4 volts happens to be 2X of 3.7 volts, and 3.7 volts happens to be the exact rating of most all cell phone batteries. Cell phone batteries can be bought very cheaply via the internet.

  2 - The next fact is that the battery door on Nikon cameras can be removed. Open it to approx 45 degrees and gently twist it out.

  3 - The next fact I would share is that a battery grip is a way to attach, usually two batteries, to the bottom of your camera. Some of the grips come with interval timers for timed exposures, they are all made in China, and as such, eBay is full of second party battery grips for many popular cameras. The grip might be the better way to modify your cameras without damaging them.

If you were to use cell phone batteries to make your own battery pack, your next challenge would be to build a charger for them, since charging them one by one would be labor intensive. Making a battery pack of the cell batteries would require them to all be the same rated capacity. Connect them in series, in pairs, to bring them up to 7.4 volts and parallel as many as you like to increase capacity to meet your requirements.

Lastly, NEVER attempt to open a battery, especially a Lithium battery. If you were to expose the Lithium to air, it most likely will explode and seriously injure you or result in your death.

Often a monitor goes dark because the back light power supply fails. Look for the power module which has the pink and blue wire back light voltage connectors. Usually there are two or four connectors for the backlight power. The capacitors on this module often fail due to heat over a period of several years, and they sometimes have bulging tops making them easy to spot. Replace all of the electrolytic capacitors on the power module, there may be five or six of them. In many cases this will restore operation of the monitor.

I have repaired several flat screen monitors, one of them was the VG2230WM. I was able to find the power supply on line and replace it after getting it open. Another one was fixed by buying the capacitor kit on line and replacing each of them. The hardest part of any flat screen repair is getting them open without damage.

Good Luck.

Generally, if you require greater precision, better stability and/or less noise, you go with metal film resistors. In the olden days, this was an expensive option, but these days, precision metal film resistors have plummeted in cost, at least for the Asian imports. So use metal film if you're working with test equipment attenuators, voltage dividers and analog timing circuits.

Metal Film Is Better
  If you need a circuit to remain within operational specs for a long time without periodic adjustment.
  If you’re designing a low-noise audio preamp.
  If you need precise timing for your 555 circuit.

Some notes here.
  1 - The ancient trick of beginning with a carbon composition resistor of a lower value than needed and filing a notch in it until the value was right on, gave you a good, tight resistor for a few minutes. But even if that notch is sealed with clear fingernail polish, carbon resistors still have a lousy temperature coefficient. The resistor will change in value with any changes in temperature far beyond what you'd want with a precision part. It isn't the same as using a precision metal film resistor, no matter what that old timer tells you.
  2 - The second note concerns power dissipation. The old carbon comp resistors could take short spikes in power and survive even with short bursts of ten times the power rating, because the mass of that slug of a resistance element could absorb and dissipate that spike. Carbon film and metal film resistors can handle their specified power level, but can't handle spikes well, for they don't have that same mass in the resistance element. They can dissipate the average rated power, but not absorb the heat of a big power spike. So, that same spike in power can cause a carbon or metal film resistor to literally burn out.

Even with the problem of film over composition described above, carbon film resistors do seem to have tighter and more stable values than the comps. They still suffer from bad temperature coefficients and noise, but the typical new 5% carbon film resistor will often be well-within 2% of its marked value.

As a "rule of thumb" I recommend: Choose carbon film resistors when low cost (at high quantity) is the main consideration. Use metal film resistors when low noise, low temperature coefficient, and/or greater precision are important.

All types of resistors generate thermal noise, also called "Johnson noise," which increases as resistance and temperature increase. This comes directly from the laws of physics which, as Engineer Scotty famously said on Star Trek, "you canna change." However, current flowing through a resistor causes additional noise, including "shot noise," and this is greater in carbon film than in metal film types. That is why the latter are preferred for critical analog circuitry, such as audio preamplifiers. Resistor noise hardly matters in digital applications.

For more information about noise, see Joe Geller's excellent resistor noise measurement project (JCan) in the July 2007 Nuts and Volts. After building the JCan kit, I could easily measure more noise in carbon composition types compared to metal film resistors of equal value when current was applied. There was no difference with zero current — just the thermal noise "background." The noise difference between carbon film and metal film resistors under power was smaller, but detectable.

The temperature coefficient tells you how much a resistor's value can change with temperature, in units of parts per million (PPM) per oC or oK. Common axial lead (through hole) ¼-watt metal film resistors are rated 50 or 100 PPM/ oC, but their carbon film cousins are 350 to 700 PPM/ oC. Sensitivity to temperature is a consideration in many sensor and measurement applications, but it does not matter in digital circuits.

Assuming the resistor offerings at Mouser Electronics (www.mouser.com) are typical of the industry, the vast majority of ¼-watt axial units are available only at 1-percent tolerance for metal film, and 5 percent for carbon film. Even if I wanted one, I could not buy a 5% metal film or a 1% carbon film resistor. Therefore, choice of type is related to precision, for practical purposes. The cost difference is negligible for small quantities; you are mainly paying for the labor to count them out and bag them.

I'm not sure about a rule of thumb but I would not use metal film resistors in an RF circuit. It would be my luck that I create a resonate circuit and have all kinds of strange oscillators going. Good Luck

I have a 555 PWM circuit diagram on one of my YouTube videos here: [url=http://youtu.be/KrcqpGZQd9U?list=PLUsDZdokq6wxDP7L3sMoYFTA5WDoAtBu4]http://youtu.be/KrcqpGZQd9U?list=PLUsDZdokq6wxDP7L3sMoYFTA5WDoAtBu4[/url] The diagram is at about 2:18 in the video. I hope it helps for starters...

There is no practical noise cancelling technology on that scale. Building an anechoic chamber would be very expensive. Playing guitar in a vacuum would not allow you to hear yourself (since sound does not travel in a vacumn), and would suffocate you. That leaves two possible options:

Relax your ban on headphones and use a product such as the $40 Amplug [The headphone guitar amp that lets you enjoy serious guitar sound, fast.]  See www.voxamps.com/amplug or possibly the low tech solution of playing under a wool blanket.

More than 40 years ago we wanted to record short skits for radio brodcast in our college dorm room. Our input was not as loud as an accoustic guitar, and we were close mic-ed for voice and sound effects. We had such good sound isolation, that it effectively blocked the external noise of nearby stereos, running feet, shouting, and anti Vietnam War riots outside the building. Many people wondered where we found such a quiet place to record! This probably will not work for amplified electric guitar. You could use a self standing tent, with covering heavy bankets down to the floor. The level ouside the tent will be dramatically attenuated.

The safety difference between a UV light bulb and a UV LED stems from the difference in radiance between the two sources. Radiance is basically the density of light in the source.

The surface area of an incandescent-size lamp is approximately 100,000 sq-mm. The source area of a high power LED is perhaps 2 sq-mm. While its likely a single high power LED will produce less optical energy than the bulb, the radiance is still likely thousands of times greater for the LED and hence its greater potential for eye damage.

In practice, as long as you don't look directly at the light source but rather the light reflected from the objects of interest, there is little difference between the two sources.