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  3. PCB design

    While you start designing your PCB, it’s a good idea to make a schematic of your circuit. The schematic will serve as a blueprint for laying out the traces and placing the components on the PCB. For a Beginner in PCB Designing, Start with Simple & user friendly software like Eagle, Proteus etc. The PCB editing software can import all of the components, footprints, and wires into the PCB file, which will make the design process easier. If you are good in circuit reading & drawing, you can easily make schematics in the PCB, through which you can create net-list & make layouts for the circuits.
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  5. IC Issue

    There are different types of ICs are available in market today. For replacing the ICs you should have to change the old electronic components from ICs like capacitor, resistor, transistors, diodes etc. Don’t feel worry about purchasing new electronic components from online electronic portals like
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  7. 0-30 Vdc Stabilized Power Supply

    Since it was years ago I do not remember which page of which thread has version 6 or 7. I have the schematic and parts list of version 6 here:
  8. 0-30 Vdc Stabilized Power Supply

    So Finally which version of schematic is correct / flawless to build the PSU ?
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  10. Biofeedback Electrodes
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  11. I was studying JK Flip Flops, i encounter a term called raised condition. I tried searching it on google but didn't found any satisfactory answer. Could any people clear me that what factors actually tends it to raised condition and how it can be prevented ?
  12. Vibratory Feeder Bowl
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  13. Build A Wooden Portable Speaker Box

    The speaker drivers look tiny, 2 inches or 3 inches in diameter like a cheap clock radio? No bass. The PAM8403 amplifier IC produces 3 Whats with high distortion into a 4 ohm speaker per channel or 2 Watts at less but still audible distortion when the supply is 5V. Have you heard the Bose little Bluetooth mono speaker? It sounds great and costs $200.00. Why is your speaker stereo? The speakers are too close together for stereo. If you made a mono speaker with the same size enclosure then the speaker driver can be larger for better bass.
  14. Circuit Diagram of D313 Power Amplifier

    This thread is 13 years old! The maximum allowed supply for a 2SD313 is 60V so the +35V/-35V is too much. If it has a huge heatsink then it can heat with 30W and have an output of 25W x 4= 100W from an amplifier. If its output swing is 50V p-p which is 17.7V RMS then the power in an 8 ohm speaker is 39W or about 70W into 4 ohms. If two if these amplifiers are bridged then the power in an 8 ohm speaker is about 137W. Peak or very distorted power is double.
  15. Circuit Diagram of D313 Power Amplifier

    Hey dear, I thought i should step in to solve this mystery. First of all D313 is an npn transistor. The amplifier you have seen is locally made by market shop keepers and amplifier maker. You are maybe from Pakistan or India. Yes they use D313 transistor mostly 4 of them with individual heatsink. They use pnp transistor for the preamplification that are a1015 or sometime what you talking about. They do operate on dual 25-0-25 ac supply which is rectified by their board to create +ve and -ve with common ground to supply to the transistor. Here is a circuit diagram. Here values are change but you can use D313. But remember one thing D313 cannot even supply 100W of power so 400W is wrongly written on the housing of your amplifier. Just to attract the customers. If there's still anything you want to ask reply to the comment. I'll try my best to help you out.
  16. High volt power supply

    I am hoping the same best work from you in the future as well. I really appreciate your work. Thanks for you agree for me. =>geometry dash =>happy wheels
  17. Build A Wooden Portable Speaker Box

    This is a sharing of a portable speaker design project. Have you ever thought about designing and building your own portable speaker? A project like this is both easy and cheap if you source your parts wisely and have basic knowledge of electronics, soldering, and box construction. The first question you have to ask is, "What do you want this to do?" If you want 40 Hz bass extension, then you will have to design for it. If you want high SPL, again, you will have to select an amplifier and loudspeaker combination that can provide that. What did I want? I wanted a portable, battery-powered stereo speaker of moderately high fidelity. Bass extension was not a concern, but "punch" was. From this, a sealed enclosure was selected. Before building the version you see above, I prototyped the circuit on a breadboard with an enclosure made from a wooden quill box that I cut two holes in with a box cutter. The basic circuit diagram for this prototype was nothing more than connecting the audio to the amplifier and the amplifier to the speakers (well, provide the power too). For reference, the diagram is shown below. (THIS IS NOT THE FINAL DESIGN, SCROLL DOWN FOR THE FINAL ITERATION) The amplifier here is a 3W stereo IC-based audio amplifier that I ordered from a Chinese website( It cost me $2. For $2, I figured I would give it a try. Pretty simple, right? Just connect it together the logical way. Now that I've shown how it went together, maybe I should share the parts list of the V1 electronics. There will be more components added in a minute. Parts List V1 Stereo 3W Audio Amplifier (PAM8403) x1 3.7V 1860 Li-Ion Battery & Battery Holder x1 1/8" Stereo Jack (or whatever you would like to use for the input) x1 SPST (single pull, single throw) Switch x1 Loudspeaker x2 (preferably 4 Ohm, I used 8 Ohm) I prototyped this circuit on a breadboard just to convince myself that what I had designed would actually work, and was surprised at the quality of the amplifier. There was distortion at higher volumes, but this was a result of the amplifier wanting 5V and the battery only capable of supplying 3.7V. I highly recommend this amplifier for all low power applications. Being as excited as I was, I quickly shoved the electronics in the quill box. I added a mute switch along the way, which was just a momentary switch connected to ground and a pin on the amplifier. It looked like this. Opening the box and exposing my hurried soldering and poor wire management... Some of the connections are twisted and taped together since I planned on transplanting it into a proper enclosure. Notice the clean sock. So, I built the skeleton of the enclosure that same night out of aspen, a soft wood that you would not normally build an enclosure out of, but it was what I had on hand and is very forgiving when I make mistakes. You can use whatever material you like to construct the box, but a common choice is MDF. MDF is made from sawdust and glue, with the mixture being compressed into the boards you buy at the store. The product is perfect for this purpose since the material is not of uniform density and does not sympathetically vibrate at frequencies we are concerned about. I chose the aspen, which you have already seen, for the sides and red oak for the front and back faces. I have tools available on this site for enclosure design, and they work great for calculating necessary box volume on a project like this. My box was build from the output of the tool and then the dimensions increased ever so slightly to lower the system resonance at the expense of system Q. I lost some of the "punch" in the bass I mentioned I was after, but I gained a deeper reach. Then I glued the rear face on the box. Designing as I went, I decided to add an "X" brace to the top of the enclosure to help minimize the low frequency energy lost to the panel. It was made from strips of 1/2" plywood and glued to the inside. Using a forstner bit, I cut two holes for the speakers on the front panel and one on the side for the audio jack and power switch. It would have been easier to cut the hole for the steel panel prior to gluing the box together, but you live and learn. Electronics V2 To mitigate the distortion at high volumes, the 3.7V 18650 was swapped for a rechargeable 9V. Since the amplifier only accepts voltages up to 5.5V, a 5V regulator was necessary. A filtering capacitor was also added to the circuit even though there is minimal noise from a battery power source. This was when the issue of charging the 9V became a problem. I had originally purchased a micro-USB charging module that would have charged the 18650, but the module's fully charged voltage was 4.7V. The regulator needs altleast 5V to let current pass. So, I had to design a charger myself. Googling a circuit to charge a 9V yielded a number of possibilities, but for simplicity I chose to go with a single 20 Ohm resistor to limit the current into the battery. There is no protection for the battery this way, but I included an LED that will turn off when the battery is fully charged. This charger also charges very slowly (approximately 14 hours for a full charge), which minimizes the risk of me leaving it on the charger too long. You will need any 9V wall-wart to supply power. The regulator and charging circuit are shown below. I then drilled two holes in an 1/8" steel plate and mounted the switch and audio jack to it. After wiring it all together, it just needed to be test one final time and mounted in the box. Parts List V2 Stereo 3W Audio Amplifier (PAM8403) x1 9V Rechargeable Battery 1/8" Stereo Jack (or whatever you would like to use for the input) x1 SPST (single pull, single throw) Switch x1 5V Regulator 10 uFarad Capacitor 20 Ohm resistor for 9V Charger Barrel Jack for charger Loudspeaker x2 (preferably 4 Ohm, I used 8 Ohm) Final Assembly Now it is done! Do you want to have a try? Then go on with it! If you have any question, please leave a comment below~Thanks for reading.
  18. Project using Raspberry pi 3

    you need to write the code in python in the raspberry pi 3 processor usign the Raspbian OS in the memory to boot up after power on using 2amp adpter generally used in mobile phone charging
  19. New Proteus Libraries for Engineering Students

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    The barcode scanners consist of an internal decoder and a cable, which are connected to the computer through compatible ports. It consists of a light source, a lens and a photo conductor translating optical impulses into electrical ones. The sensor of the barcode scanner detects the reflected light from the illumination system and generates an analog signal with varying voltage which represent the intensity or lack of intensity of the reflection. The converter changes the analog signal to digital signal which is fed to the decoder.
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  23. Help Under standing Schematic PSU

    Hi Islam, Thanks for letting me know I helped, that is thanks enough. Makes it worth the effort.
  24. Help Under standing Schematic PSU

    Hi Islam, I'm a new user here (just signed up to answer your question), so I hope this helps. There seems to be several things that need to be understood about the overall topology of this PSU to get to answering your questions The power supply has two main parts: 1) The control section with the GHI outputs from the transformer, generates +12, -6, and -15. The ground of the control section (center point, more or less) is connected to the Positive side of the output. See ground below C4, and on the far right of the page (has the number 15 near by). (I think these numbers scattered through the schematic are test point numbers). So all of the control circuitry (anything using +12, -6 and -15) Is referenced to this ground. What is a little surprising, is that means that as the power supply output goes up/down, the control ground is doing the same. Also on this signal, is one end of the each of the six Load-Balance/Current-Sense resistors (6 x 0.36 Ohms). 2) The second part is the power section, which includes the lower half of the transformer (ABCDEF), the relays that select between the 4 voltages you listed (15-20-30-50), the bridge rectifier D7..10. The Negative side of the bridge is directly connected to the negative side of the output. (the line at the bottom of the page with label 14.) The Positive side of this bridge rectifier goes to the 6 collectors of the 2N3055s, then the 6 resistors mentioned above, then to the Positive side of the output, which as described above is also the ground of the control electronics. Since the maximum current is 3 Amps, and it will be shared evenly between the 6 resistors (with very minor differences depending on the exact characteristics of the six 2N3055s), the maximum current for each resistor is 0.5 Amp. So the max voltage across these resistors is 0.18 Volts , which gives about 90 mW , so these resistors are grossly over-sized at 5W, and will run cold (unless they are mounted on the heatsink). This also means the voltage on the 6 emitters is 0.00 to 0.18, which is averaged by the six 100 Ohm resistors and then sensed by U2 which implements the current limit circuit. U3 implements voltage control, follow pin 2 to the right which goes to the ground symbol, which we have established is power supply's positive output, and pin 3 which is connected to a voltage divider (including the front panel control) which connects to the negative side of the power supply, marked with the label 14. So now to get to your question. Regardless of what the output voltage is, the six emitters are no more than 0.18 volts above the ground of the control circuits, which tracks the positive output of the supply. The bases of these transistors will be 0.6 to maybe 0.75 volts above that. So the base voltage is always in range of the control circuit driving it. For the same reason, the 2.5V reference is an offset from the control section ground, and the power section's positive output. Yes, the six resistors also carry the base current, but this is minimal, compared to the collector current, due to the gain of the transistors. At DC, 25 deg C, and collector current of 0.5 Amps, the gain is over 100. I just did a Science (see picture below) to make sure I wasn't lying: With 15 volts on the collector, I got the following results: Vbe Ib Ic Volts mA mA 0.5 .05 3 0.56 .15 22 0.6 .36 82 0.61 .5 122 0.63 .7 190 0.65 1.0 280 0.67 1.26 370 0.7 2.2 600 (Note, Vbe is using the voltmeter in the PSU, which is not very accurate, and the transistor heated up on the last few measurements, and needed to be cooled) Anyway, the measurements I made show a gain on my test 2N3055 of about 300 when the collector current is around 0.5 amps which is the high end of what is expected in this power supply, and would contribute about 0.3% of the emitter current. Thinking a bit further, it doesn't really matter since it is sensed along with the collector current, and it all goes out through the positive output of the supply. Cheers
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  27. Back to back AAA cell whim, bad idea?

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