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Everything posted by Omni

  1. Maxim released another excellent stereo audio vol/balance IC that is very versatile, take a few minutes to review the data. http://www.maxim-ic.com/quick_view2.cfm/qv_pk/5288
  2. audioguru is completely correct in his view! In the event you are interested in RC helicopters about the best advice i can give is to STOP viewing the short mpeg video clips provided by many manufacturers! The latter outlets use highly professional (seasoned) RC pilots that make it look extremely easy! Before purchasing a full gas/electric copter consider buying a good simulator (Real Flight), the latter will give you a peek as to the difficulty required. :( A helicopter is a flying contraption that requires a lot of patience and skill; continual corrections are required to keep it stable, even with a gyro! The only difference between flying a model RC copter and the full scale mechanical nightmare is the pucker factor! Ah, you probably get the idea? ;D
  3. FM transmitter's of that type can be very directional. You could also add a powered Omnidirectional Microphone for added preamp gain (very sensitive). :)
  4. Take a couple of hours and review the data sheet .pdf for each device. :)
  5. Hello AN920, You could also review quantum tunneling which has a very similar outline. Where the wavelength of a particle's wave function is inversely proportional to the momentum of the electron. The concept behind negative resistance has been discussed a long time ago; noted in klystron/magnetron tube theory. However, today the theory is actually being applied in a more versatile manner.
  6. Wait a second... Remember, fuel cost! ;D
  7. Haha, I must admit i tend to avoid a big confrontation when silicon is concerned... When i received my degree the class was just starting to delve into transistor theory. :o Within the University i continued to attend, advancing my degree during the evening curriculum but as everyone is aware the evening program is sort of loose. :-X When i view the mental focus of AN920 i get a smile, she is very precise; how i was when learning the fleming valve but without all the simulators. Oddly, during the fleming heyday (Rf) i considered a smith chart a type of simulator! ;D Today, with all the mini surface mount technology i am a little lost to say the least. :-\ However, i am from a far different era where one could hold the actual part and clearly read a part number etc... My time with electronics was very enjoyable and i still find interest in designing and engineering musical tube amplifiers, primarily push-pull. The odd, young character/avatar is a pseudo comparison i found humorous! ;) Plus, i attend Mass on a regular basis, i have found that the latter is more important than anything else; my opinion. :)
  8. Hi Pawel_K I was finally able to view your pics. When viewing the NS (near-side) of the PWA (printed wiring assembly) i noticed two resistors that may be incorrect. 1. Lift one side of R7, using a VOM measure the resistance it should measure 0.47 ohms or 1/2 an ohm (not 47 ohms). You may have the correct value but it is always a good idea to make sure. 2. R1 should be a 1W type, when viewing your picture it appears to be a 1/2W, the latter could be the reason why it is becoming hot. Hi Audioguru, Yes, you are correct concerning the transformer secondary current, a 33% reduction would make a big difference...
  9. Hi TJBraza, http://www.analog.com/UploadedFiles/Data_Sheets/ADT7485A.pdf Although, it will probably require a small program written in C or Visual basic to convert the string MSB & LSB into a more easier read etc... Take a moment and review the data sheet, the IC has a lot of potential.
  10. Hi AN920, I have to agree on your analysis concerning the biasing (quiescent point) of the TIP31A in reference to the error amplifier outlined. A TIP31A is usually implemented as an output transistor and/or as a complement to the TIP32A etc... A transistor with a faster response would be a better choice in this application. Without trying to apply a large re-selection of silicon one could easily use the original components and simply drop the selected secondary current of the main transformer to avoid current issues. When i completed the project i used the original design as stated in a prior post with very satisfactory results. Your graph analysis is very professional and commendable! ;)
  11. Sorry, but i am unable to view the pics; Java? You should upload your pictures to Photobucket (or similar hosting server) then provide the URL etc... The supply does operate properly but i must admit i jumped on Audioguru concerning a current issue and he may be correct. Yesterday, when viewing the internal of the P/S i noticed i used a 2A transformer... :o Additionally, after reviewing the data i compiled the controlled current max was verified at @2.00A :-[ I implemented the original design without any component substitution other than the main transformer which was reduced in secondary current to 2A. Phew, i tend to grab/substitute components i have on hand etc... :-\
  12. Hi Etinios, Your professor must have provided more information concerning the planned project. I believe more detail is required for the forum to provide direction. -Omni
  13. The cathode is generally pulsed with a negative potential using a HV DC source, within the core of a circular chamber the latter cathode is placed. Angular to the core a magnetic field is constructed which in turn allows the electrons to spiral out in a circular pattern to the anode. Provided around the outer edge of the core are additional cavities, as the electrons pass the latter opening they resonate at a high frequency. The circular pattern cause the electrons to push together (group). A small amount is forced/directed to a metal tube (WG), the waveguide emits the high Freq RF energy to the cooking containment area for heat etc... Actually, the above process is similar in relation to a klystron tube but much more efficient. Although, a klystron is better suited for other applications; High power transmitter etc... Final note: Use caution around any HF wave when experimenting since radiation is emitted in a dangerous manner when uncontrolled; dont take the path of Madame Curie... -Omni
  14. When the start button is depressed a three part timing cycle occurs. 1. Main motor begins to feed the paper CW. 2. After a few seconds the lower motor begins to turn CCW to wrap the paper. 3. Once the latter length is achieved the first two events end and the cutting tool completes the tear. All of the above can be performed easily with three 555 timers, calculating the RC time constant in reference to the required timing concerning event 1, 2 & 3. Additionally, all three motors will require a calculation to determine proper gearing. Although, event 3 can utilize a simple servo; again, a geared motor. Furthermore, more than likely all three 555 timers will each require an output transistor and probably a mini relay to sink the motors correctly. View the .pdf data sheet concerning the 555 for more information concerning how to calculate the required RC timing for each event. The design will require both mechanical and electrical knowledge.
  15. Hi AN920, I admire your candor! You appear very young in your Avatar picture. In the event it is authentic than you will have a lot to give to the younger engineering community because of your age! :) God bless, -Omni
  16. The 1MHz CPU addressed to the C64 fell off the edge of the World awhile back... :o Today, the only use for the C64 & C128 is noted as a vintage collectable. Although, i must admit for gaming purpose the package aesthetics along with the finite code practiced was optimum. Software engineering today abuses the fast CPU because the programming they create is very sloppy! C64 software was pure assembly language ~ (similar with today's VVM); very fast and accurate! Even the basic emulator used with the C64 (Peek - Poke) was presented in a fast format. Sadly, their are a few limitations when using assembly that for the most part can only be used in a focused application. The "Sprite" command was very useful in the past (C64) but with the variety of colours we are use to today the latter function is simply resolved into the primary band etc... Zombie, you are one of the very few that can keep the fabric of the C64 alive, similar to the great people that have the desire to uphold the old HERO (Heath Robot). I admire your dedication, the latter will allow the younger community to see first hand where the (somewhat) beginning elements occured! I myself design and engineer Tube amplifiers for the very same reason. ;)
  17. "the probe was defective.it was made of paper clips..." Hehe, if you are every stranded on a deserted island i am sure you will survive!" ::) Good job! :)
  18. http://www.aaroncake.net/circuits/volume.asp http://datasheets.maxim-ic.com/en/ds/DS1669.pdf I do not know a lot concerning the circuit provided since i have yet to experiment with the IC but the above links may provide the info you are looking for; appears simple enough. When used in a stereo mode i imagine you would use two of the ICs along with two DPST N.O momentary push button switches. Although, it may be easier along with less expensive to locate 2 DPDT momentary pushbutton switches and only use half the switch etc... You could also Google the IC part number where more circuit design may be available. :)
  19. Hi friends, Anyone aware of a service manual/calibration manual for the Metrix OX8100? I exhausted Google but have come up empty... Any link would be appreciated. -Omni
  20. The only issue i am aware of concerning a nuisance trip when using a GFCI would be motor control circuit. Occasionally, a motor/pump circuit can draw a large inrush current that will trip a GFCI. The latter is one of the main reasons why a GFCI is rarely installed on a refrigerator branch circuit. Furthermore, you can configure your bench with the availability of GFCI and a conventional receptacle in the event the latter receptacle is necessary. "I can't imagine that it's that unusual for safety to be a priority when it comes to electronics - I can't see how it *wouldn't* be an obvious concern." Oddly, an engineer usually doesn't pay much attention to safety since the majority are designing and/or troubleshooting around low voltage. Where as an electrician has the utmost emphasis on safety since he/she is generally working on a voltage that is deadly.
  21. I hold an EE and EC License in three States, your idea of using a GFCI is excellent! Safety is so very important! :) Furthermore, down the road consider purchasing an isolation transformer and/or a variac! However, make sure the Xfmr or Variac has a decent current capability; 20A Remember, do not get the above confused with a ground wrist strap! A wrist strap is connected to ground through a coiled retractable cable and 1 megohm resistor. The latter allows high-voltage charges to leak through but prevents a shock hazard when working with low-voltage parts. When higher voltages are present, extra resistance (0.75 megohm per 250V) is added in the path to ground to protect the wearer from excessive currents etc... Excessive HV (RF amplifiers) that use larger voltage/current to excite a tube should refrain from using any wrist strap and/or anti-static smock etc... The latter will only produce more danger and risk of electrocution. A lot depends on what you plan to troubleshoot and/or design. Your one of the few that view safety as a primary caution!
  22. Final note: Use precaution with the above circuit and read the directions provided with the project! I agree the circuit requires a bit of changes but to a certain extent it may provide some information. Truthfully, i would purchase a manufactured inverter for safety along with warranty etc...
  23. I admire your idea but what you are asking for is not an easy task. Truthfully, if you surf the web concerning the vehicle you own in reference to digital auto guages the package may already be available as a plug-in. People get the impression that building a kit or designing/constructing a project will provide a savings concerning cost. Sadly, the latter is generally incorrect, a small simple circuit will allow a savings but a large project will usually cost more. The other dilemma you encounter with your project is the environment, extreme cold (winter) and/or extreme hot (summer) place a toll on a project not designed for the purpose. Cheap, inexpensive parts concerning the above will only create a lot of frustration down the road.
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