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  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
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