mixos

Thanks for sharing it with us? :D GREAT jod! I will add a link also.. at the links section. A little bit later...... Here it is: http://www.electronics-lab.com/links/?c=79

Check here: http://www.hanssummers.com/electronics/clocks/clocks.htm some great clocks... but are stand alone.

The conversion of electrical pulses to mechanical vibrations and the conversion of returned mechanical vibrations back into electrical energy is the basis for ultrasonic testing. The active element is the heart of the transducer as it converts the electrical energy to acoustic energy, and vice versa. The active element is basically a piece polarized material (i.e. some parts of the molecule are positively charged, while other parts of the molecule are negatively charged) with electrodes attached to two of its opposite faces. When an electric field is applied across the material, the polarized molecules will align themselves with the electric field, resulting in induced dipoles within the molecular or crystal structure of the material. This alignment of molecules will cause the material to change dimensions. This phenomenon is known as electrostriction. In addition, a permanently-polarized material such as quartz (SiO2) or barium titanate (BaTiO3) will produce an electric field when the material changes dimensions as a result of an imposed mechanical force. This phenomenon is known as the piezoelectric effect. Piezoelectric Effect (PPT, 89kb) Source: http://www.ndt-ed.org more here: http://www.ndt-ed.org/EducationResources/CommunityCollege/Ultrasonics/EquipmentTrans/piezotransducers.htm I think that Piezoelectric Transducers are used to our mobile phones to make them ring, or i am wrong ?!

The LM317 calculator is here: http://www.electronics-lab.com/articles/LM317/index.html be sure to check it . ;)

Datasheet 8085 http://digilander.libero.it/rar2k/TRS80/Intel8085A.html Datasheet 8255 http://jap.hu/electronic/8255.pdf Datasheet 8251 http://www.moxsyn.com/@ltera/c8251.pdf Datasheet 80c85's http://www.oki.com/semi/datadocs/doc-eng/msm80c85ahrs.pdf Datasheet 82c51's http://www.oki.com/semi/datadocs/doc-eng/msm82c51a_2rs.pdf

The best site around ATX power supplies (or generic switch mode power supplies) ;) : http://repairfaq.ece.drexel.edu/sam/smpsfaq.htm Nice pdf billy :D

When i tryed to test the software alone (without hardware) the same error apears in Win XP Pro. This is clear that has to do with the software constuction. I suggest to e-mail the author here: natan[nospam]email.si (don't forget to replace [nospam] with @) Also try to istall this on your system: http://www.electronics-lab.com/projects/pc/020/port95nt.exe Or try this PC thermometer: http://www.electronics-lab.com/projects/pc/016/index.html I have tested it and it works nice, it works with the joypad port. Don't forget to report back any corrections.

Can anyone suggest any interesting chips that availaible as samples? I am starting with some: MAXIM MAX038 - High-Frequency Waveform Generator DS1869 - 3V Dallastat Electronic Digital Rheostat ICL7107 - 3 1/2 Digit A/D Converter LED DS1920 - Temperature iButton DS1620 - Thermometer Sensor TEXAS INSTRUMENTS TPA1517 - 6-W Stereo Audio Power Amplifier TMP100 - Digital Temperature Sensor with I2C Serial Interface UC3770 - High Performance Stepper Motor Drive Circuit MICROCHIP MCP42100 - 100 K Digital Potensiometer PIC16C765 - 24Mhz, 256 RAM USB, USART, 8ADC, PWM 2, 3+WDT any others?

Here are the rest ;) : 39VF160 Flash Memory www.mcu-memory.com/datasheet/sst/39vf160q.pdf http://www.sst.com/downloads/datasheet/S71145.pdf

Great Work Billy. Thanks for doing that :D . Sometime ago an internet friend told me that the kit companies are making some small faults (not by chance) on schematics to prevend them from copying :o ! If you relly on the PCB, everything will work nice, becuase it's a copy of the original (already worked) board. So you can use it to debug the schematic. Please do the debuging and make the changes to the schematic... i will be very happy to see it here!

The transformer i bought was rated at 3A, but seems to be able to give more that this :D ! Also i didn't touch anything on the current limiter circuitry, I just set the current limit to full, that the strange! Staigen: I haven't done the testing yet. Sorry for that, you will have to wait some days.. ::) By the way, I am happy you are an expert in PSUs that's give me some hopes to make this power supply even better :D, we hope to continue sharing your knowlebge with us! But can you be a little more detailed... Why the case must has a 25 C, and not let's say 120 C (200C is the max temp that can affort this part) with a radiator of course. "At 3 Amp output the rectifier is delivering about 100 Watts" Why so much watts? Please help us understanding how you think in every result you post. So less experienced peoples will learn something! Hope i am not getting bored.

Yesterday I received a report from a user, read it: I have an update for you regarding the transistor tester as I was having a few problems in getting it to work well it works now as a few modifications have been added such as connecting pin 8 of the 4027 to ground and then linking pins 3 and 9 of the 4027 together it then works. once again many thanks mike it is a good site. keep up the good work from kev Tellyaddict42[no-spam]aol.com . Anyone that don't succed with this transistor tester can try this solution and post comments here so i will make any suggested corrections on schematic. Thanks

Check this: Mini-box 2W Amplifier 10W Mini Audio Amplifier The first uses 12V and the second 9V. To power them from your vehicle you can use 78xx series regulator. Hope you like them :).

I found it on another forum on the internet... it was uploaded by a user :P .

I build it and give me around 4A output max, but i didn't let it for long time. I have not made any measurements on ripple because i haven't an oscilloscope at home, but i will do the measurements as soon as possible and i will post the results here. What you suggest to use as a low voltage - high current load? Also can you drive us to the right direction to convert it to a 5A or more PSU? Q4 = 2N3055 it's rated at 15A max current as datasheet mentions. So it's ok to use it for higher currents. The changes must be done on other parts of the circuit. Am i right?

Let's give a try to this: How can we convert the following adjustable power supply which is rated at 3A max to 5A or more. It has a current limiter circuit and 0-30V output. Curent Specifications: - Input Voltage: ................ 24 VAC - Input Current: ................ 3 A (max) ------> make it 5A or more - Output Voltage: ............. 0-30 V adjustable - Output Current: ............. 2 mA-3 A adjustable - Output Voltage Ripple: . 0.01 % maximum - Reduced dimensions, easy construction, simple operation. - Output voltage easily adjustable. - Output current limiting with visual indication. - Complete protection of the supplied device against over loads and malfunction. If we succed, it will be the best bench power supply available on the internet. Let's discuss the ways we can do that. You can find it here: http://www.electronics-lab.com/projects/power/003/index.html The schematic is the following:

Here is a list of guides on how to drive Nokia Phones LCD diplays. There is not a specific for 3310 but maybe there is a suitable. Check them: How to drive a Nokia LCD, type LPH7779, LPH7677 or LPH7366 with PIC16F84A Nokia7110 LCD, type P313032901 , driving library 7210 LCD Pinouts 7650 LCD Pinouts 7110 LCD Pinouts 3510i LCD Pinouts 6310 LCD Pinouts

If you are searching the datasheet, here it is: Download MT8880 Datasheet Also here is some projects that uses this DTMF Tranceiver: http://www.technology.niagarac.on.ca/students/m/smcgrath/ http://hem.passagen.se/communication/ir.html so you can take some ideas on how to use it. Also here is a DTMF basic guide: http://www.hw.cz/english/docs/dtmf/dtmf_doc.html Hope that info helps you a bit.

Yes, LM7805 is suitable for 24V input, it can take as input even 30V according to the datasheet i attach. The capacitors are used to smooth the input-output voltage. LM7805.pdf

You will find a good Digital LED Voltmeter here : http://www.electronics-lab.com/projects/test/014/index.html It uses 7107 and can easily converted to a Digital Ammeter. Below i attach the basic connection diagramm with the connections as a voltmeter and as a ammeter. Also read this: http://www.electronics-lab.com/forum/attachments/Digital_Panel_Meter.pdf It's true that you need to connect a load to the output. Read this to understund how to current limiter works. Current Limiter Function Another very important feature of the circuit, is the possibility to preset the maximum output current which can be drawn from the p.s.u., effectively converting it from a constant voltage source to a constant current one. To make this possible the circuit detects the voltage drop across a resistor (R7) which is connected in series with the load. The IC responsible for this function of the circuit is U3. The inverting input of U3 is biased at 0 V via R21. At the same time the non inverting input of the same IC can be adjusted to any voltage by means of P2. Let us assume that for a given output of several volts, P2 is set so that the input of the IC is kept at 1 V. If the load is increased the output voltage will be kept constant by the voltage amplifier section of the circuit and the presence of R7 in series with the output will have a negligible effect because of its low value and because of its location outside the feedback loop of the voltage control circuit. While the load is kept constant and the output voltage is not changed the circuit is stable. If the load is increased so that the voltage drop across R7 is greater than 1 V, IC3 is forced into action and the circuit is shifted into the constant current mode. The output of U3 is coupled to the non inverting input of U2 by D9. U2 is responsible for the voltage control and as U3 is coupled to its input the latter can effectively override its function. What happens is that the voltage across R7 is monitored and is not allowed to increase above the preset value (1 V in our example) by reducing the output voltage of the circuit. This is in effect a means of maintaining the output current constant and is so accurate that it is possible to preset the current limit to as low as 2 mA. The capacitor C8 is there to increase the stability of the circuit. Q3 is used to drive the LED whenever the current limiter is activated in order to provide a visual indication of the limiters operation. As you understund you can measure the "preset voltage value" adjusted by P2 and convert that value to the corresponting current limit set point in a way. Hope that drives you to the right direction.

I use this digital voltmeter with this 3-30V power supply: http://www.electronics-lab.com/projects/power/032/index.html If you configure it at 200V range (R3 = 12K) then it will measure from 0-30V with one decimal point precision. for 4,1V will display: X04.1 for 10,1V will display: X10.1 where X indicates that the first display is OFF I think this configuration is ideal for your power supply. If you finally draw a PCB for a complete bench PSU solution i will be happy to host it under the power supply's page ;) .

This power supply is exactly what i was thinking about. But it's difficult for me to desing it also :-\. Let's wait a more experienced user to drive us to the right direction! Meantime, i suggest you to read: 0-30 Vdc Stabilized Power Supply With Current Control 0.002-3 A http://www.electronics-lab.com/projects/power/003/index.html which has current limiter circuit so you can take some ideas. Also i have to make another "feature" proposion: You can replace classic pontesiometers with DS1869 digital pontesiometers and have up down push buttons for adjusting the voltage.

That's a good idea converting a bulb flash light to a led one. It will become a power saving device with the same efficiency. If you visit: http://ledmuseum.home.att.net/ you will find many interesting led flashlight projects. Also check: http://www.jens-seiler.de/bastelecke/jarlight-en.html http://www.web-ee.com/Schematics/LED%20Flashlight/LEDflashlight.htm http://www.e-f-w.com/community/modules.php?name=News&file=article&sid=32

You can check if 555 is ok by measuring the output pin 3. It must has a 12Hz signal. To do that you must have access to an oscilloscope or a digital multimeter that measures frequency. Alternativally you can replace 555 to be sure it's ok. Keep in mind that the most common problems are at the connections. Double or triple check them in different moments in a day so your mind is clear. Also make sure you really understand the connections reading the schematic and there are not confusions.

Dear billy I am glad to hear that this method works for you. I haven't tryed it yet myself. It would be nice if you scan your pcb and attach it to the forum, so we can see the quality of the result. I suggest you to use 300-350dpi resolution. If the pcb is big send as just a part of the pcb (use as high resolution as to keep the file size in acceptable size). Hope you can do that.. for us !! :D