MP

steven, you might be pleasantly surprised. I recommend you continue with your project with an open mind. MP

Did you over heat the UCN chip? You probably need to build one of the other designs if this is the case. MP

You would compensate for this in the software. MP

The transformer that you choose will make quite a difference as to what you get out of this device. I assume the kit gave you a recommendation. You should be sure to get one as good as the recommendation or better. Regarding the 2N3055s, it does not matter which manufacturer as long as the transistor specs are correct. MP

Good subject to expand on. Again, if you are only blinking LEDs, it might not matter. The individual resistors in the design from the French website give you a more universal device that is not limited to using the same common for all outputs. Thus, it has the capability of other applications. In an LED circuit, the individual resistors in this design give you the capability to use different types of LEDs where they will need different currents. If you will always use the same LEDs and the same common, you can save a few pennies by using a common resistor such as in the Bowden design. MP

Chris, There are actually two projects by this name in our projects section. I think the project lists the tolerance, but why don't you post a link to the one you are making and then everyone will be able to give you the most accurate advice. Also, have you seen the other longer threads in this forum? There has been some very thorough discussion on one of these projects. MP

The carry out will allow you to use multiple 4017s as ones and 10s type of counter. You do not want to use this for a continuous counting sequence. Bill Bowden's circuit does not make a very good tutorial and I would recommend using the AND gates. I would also use gates for the clock instead of 555 if accuracy is required. Of course, if you are only blinking lights, neither of these two points matter, since the inaccuracies cannot be seen by the eye. Below is the link to a site that shows several 4017s cascaded correctly. If you follow the way that each triggers the next and the last step resets the circuit, you will learn how to cascade as many 4017s as needed. I think it will act as a pretty good tutorial for those who have questions about cascading this chip for multiple LED strings. http://etronics.free.fr/montages/eflum/EF01/EF01.htm On this site, click on the link "Schema ef01.pdf" to get a larger schematic in pdf. MP

Have you made one of the blinky light projects with the 4017? If so, you know that the clock frequency causes each output to fire off in a controlled sequence. Thus, if your clock signal causes each of the LEDs to blink at every 0.5 seconds, you could select the pins you want for a pulse every 0.5 seconds, 1.0 seconds, 1.5 seconds, etc. Of course, you are not lighting LEDs, but are using the outputs for pulses, instead. For example, output pins 1 and 4 would probably give you a pattern like your timing diagram and you would need a 12th sequence to re-trigger the first again at the correct timing. To get a 12th sequence, you will have to cascade 2 4017s. You basically have a 0.5 second time base and you can choose which increments you want to use until it loops back and starts over again. MP

The most accurate way to do this is to use a crystal oscillator and a divider circuit. It can also be done accurately with a micro, since you program the timing. This is basically the same as a programmable divider since all functions in the micro are based off the clock cycles of the micro. MP

If a 5 volt amplitude is desirable, you could use a clock circuit and some logic or clock circuit with 4017s where you choose the output pins that would give you the correct timing. For a more accurate source, you could use a microcontroller. Turn the port pin on, start a 500 millisecond count, turn it off, start a 1 second count, turn it on, start a 500 millisecond count, turn it off, start a 4 second count, and loop (repeat). Such a circuit would only require a cheap micro, a clean 5 volt source, and a resonator. MP

What is the amplitude? Does it only produce this one set of two square waves or does it repeat this sequence? If it repeats, does it give a defined number of repetitions or is it continuous? MP

Steven, It looks like a nice little kit. It is a shame they didn't include the transformer and heat sinks, but it looks like a nice simple kit for those who do not need a lot of power. Where will you use it? Did you purchase the kit for a specific purpose or for learning about inverters? MP

Would something like this work better? http://www.tekscan.com/flexiforce/specs_flexiforce.html Just a thought, since you are re-designing it anyway. MP

Rory, The project does not go into depth about what type of input signals it can handle. From your description about how you turn it down to almost nothing to get rid of the distortion, is a symptom that you are overloading the mixer with your input signal. You need a different design. What are the signal specs? Do you know the voltage of your signal? Current? Frequency range? MP

There are probably as many different LCD displays as there are models of cars in the world. You will need to find something specific to what you will interface it to. Color, B/W, 1 line, 2 lines, 4 lines, character, graphic, etc.... There are many variables. Depends on what you will interface to it. One good source is www.earthlcd.com MP

Trienbang, Your DIP or SIP packages on this board most likely have their holes on 0.1" centers (2.54mm). It is pretty standard. Print and measure, then tweak on the size if needed. MP

Hi edeca, Sorry for the late reply. Yes, you could use a charge pump circuit to get you the slow signal that you want. There are probably a lot of different ways to do this. One way to do it is to use CMOS switches. Also, some digital gates with capacitors to smooth out the signal would work. A slow sine wave oscillator could also be used for the front end of a circuit like this. You would need to look at the possibilities and choose what suits you best. MP

Linx Technologies makes small RF transmit and receive chips that run on low power. Perhaps you can find something on their website that will be useful in your project. http://linxtechnologies.com/ MP

I am not sure why your simulation fails since I rarely use any of the simulation software packages. However, to answer some of your other questions, the LEDs will each go on and then off as the signal is sent to the next LED when using a 4017. Use of large capacitors on the LED side of the 4017 would give you some delay, but would not keep them on like what you want. Another method you could use to achieve this goal is to use a LM3914 as a voltmeter setup and feed the varying steps of voltage to the chip to cause the LEDs to light up in sequence. The LM3914 has the capability to keep the LEDs lit as you progress. This is how audio meters are made, with the exception that they use the LM3915, which has a logarithmic progression instead of the LM3914, which has a linear progression like what you want. I noticed that you mentioned a PIC programmer. Another method is to use a microcontroller to run a timer and set the ports high or low as needed. MP

You might have to look at the data sheets for the parts and simulate what is actually in the individual chip packages for FPGA programming in this development package. I am not familiar with it. Perhaps another member of the forum also uses this package. You might also try a post in the programming forum. MP

I am not familiar with your program, but you should look for 4511, 4518 and 4060 chips. Forget the MC1. You won't see that in your list. Does that help? MP

Joe, Here is a circuit for a 0 to 60 second stop watch. This should work for your purpose. It has "hold" and "reset". MP

One thing to keep in mind if you are adding the opto coupler in series with the existing LED is that the opto coupler has a LED in it which is going to drop your voltage and change the available current to both devices. When calculating current in a circuit with an LED, you always subtract the LED voltage drop from the circuit before dividing into the value of the resistor, thus, in this design, you might have to remove the resistor in the original circuit and replace it with a different value. Not a big change, but something to be aware of in case the original limiting resistor will only feed the existing LED. MP

It is not a good board layout practice to use a board layer for this purpose. MP