Hero999

How much are you willing to pay for someone to design the whole system for you?

Maybe the first thing you should learn is that RadioShack is a poor place to buy electronic components. It's much better to look online, most people here buy from: Digikey, Farnell and RS Components because they stock a greater range, at more reasonable prices. RadioShack have a limited selection of often poor quality parts for several times the price. What interests you? Looking for online electronics tutorials is a good starting point.

What's the Ah rating of the batteries, at the current drawn by the glow plugs? You do the calculations.

You need batteries with a high enough energy density. Reducing the voltage will do nothing, read up on Ohm's law, for a given amount of power (in this case heat), the current will need to increase proportionally, if the voltage is lowered. In your case, each glow plug requires 120W and you want it to last for 15x50 seconds, so the battery needs to be able to store at least 120x15x50 = 900kJ of energy. Simply put, a 1Ah 1V battery can provide 1A@1V for an hour which is 60x60 seconds, E = 1x60x60 = 3.6kJ. In reality, it's much more complicated, the voltage would drop as a real battery discharges, many batteries only deliver a fraction of their Ah rating at high currents and some batteries can't be fully discharged without being damaged, so you'll need a far greater Ah rating than the theoretical value,

Simply short circuiting a capacitor is a bad idea because the current will be very high so could weld the wire to its leads. It's much better practise to discharge it using a resistor to limit the current to under 10A. A word of warning: obviously be careful around large capacitors charged to high voltages (above 60V) and beware that dielectric absorption can cause a discharged capacitor to recharge slightly. I'd recommend keeping the capacitor terminals shorted for a couple of minutes before conducting the test. The method you've described only works for large value capacitors (<100uF or so). It won't work with a 1uF capacitor. The voltage rating of the meter makes no difference.

I wouldn't show a student the right way. Believe it or not, that wouldn't be helping them at all in the long run. It may help them pass the assignment but it wouldn't help them with the exam or when they get a job and have to do it for real. I'd help the student by giving hints about what they're doing wrong and let them figure it out. I've never heard of ProtoLab so I can't help you with the specifics. If you can't find the model for the transistors you used, I suggest you create your own from the parameters given on the datasheets. You need to label the schematic properly. Give each component an indent, i.e. C1, C2, Tr1, Tr2, R1, R2 etc. That way people helping you can refer to the components on your schematic. You could flip some of the components to make it easier to read and save the schematic as a .PNG or .GIF file. JPG is designed for photographs and is a lossy format so gets fuzzy after a few saves. Going back to the schematic. On the right you have a 2A constant current source (call it I1), connected in parallel with the 36V power supply (V1), with the ammeter connected in series (M1) and reads 1.62A. Can you figure out the current actually drawn by your circuit? Try removing I1 and noting the the reading on M1.

Wrong prefix again, 79.9MV is 7990 000V, 79.9mV is only 0.079V http://en.wikipedia.org/wiki/Metric_prefix An LED needs at least 1.8V to work. My guess is the actual peak voltage is more like 3V but it's so brief your meter doesn't have time to respond to it. If you connected it t an oscilloscope, you'd probably see a 3V pulse. Don't forget this is with you tapping the ear phone so the voltage will be much higher than if you were to place t next to a noisy object.

You forgot the schematic.

I know it can pick up engine sounds. My concern is that the flashing LED part may not work as there are many harmonics given off by the engine. If you just want to listen, then fine but don't expect it to be able to flash the LED every time the injector fires. Fuel injectors are powered off 12V. The only high voltage present in a car is the ignition system and is typically no more than 10kV. You've got your prefix wrong there, you mean 28mV which is just 0.028V which is nothing, and you must've got the decimal place wrong as it isn't enough light an LED.

This circuit won't differentiate between one sound and another, that's much more difficult to do. It sounds like you're doing it the hard way. Why not connect an LED and resistor across the injector coil, or if you don't want to make physical connection, use a coil to detect the injector coil's field.

I'm sure you ca figure this out for yourself. Hint: the floating ground behaves like a 6V voltage source, in series with two 4k7 resistors connected in parallel.

Why do you have what looks like a current source and voltage source connected in parallel? It will inject 2A into the voltage source so the ammeter's reading will be equal to the amplifier's total current consumption (which is almost nothing when there's no signal) minus 2A. Is the 10R resistor supposed to be the load? If so Why is it in series with 0.1uF?

What do you mean by link the program together?

How are we supposed to help you with the #pcb when you haven't posted the layout or a photograph? Is the PCB layout similar to that given on the datasheet?

What I meant was are you sure the models used are accurate? For example, have you included the ESR of the inductors and capacitors? If the the answer is no, then your simulation is wrong.

Good, you've realised you won't get any help, unless you give enough information. Are you sure the simulation is accurate? Have you assumed ideal components? What about the PCB (which again you've not posted so we don't know)? Is it correct. Have you followed the layout recommendations of the SMPS IC manufacturer?

Apart from the fact, the circuit is wrong, you need to change C1 from an electrolytic to ceramic capacitor.

The recovery time is the only thing you need to be wary of. At 400Hz it shouldn't be too much of a problem. The power dissipated at 400Hz would be slightly higher than it wouls be at 60Hz. I'd advise selecting a part with a higher current rating than you need, go for 25A or 30A.

Firstly, why are you using a power op-amp to simply drive a motor? It seems like a bizarre thing to do. A single transistor would be much cheaper and more efficient. Are you even sure the op-amp can supply enough current to power the motor? You're right about the formula to calculate the RMS value of a square wave, what you've missed is your cheap meter probably gives the average value, rather than the true RMS value. If you used a higher quality true RMS meter, you'll discover it reads the correct voltage.

When the server went down a couple of years ago, lots of old attachments went missing and the administrator couldn't retrieve them from the backup. Sorry, there's nothing I can do about it.

How old is it? Some old attachments have been lost. Please post a link to the post.

What do you need help with? Please post your work so far.

It works for me under Windows XP 32-bit. Simply extract all the files to the same folder and run ECD.EXE This is an old DOS program so won't work with the newer versions of Windows (Vista, Windows XP 64-bit or Windows 7) but it should work under an emulator such as DOSBox.

It's fairly straightforward with a DC motor or AC motor. The motor's impedance reduces (therefore drawing more current) as the mechanical load increases. A current limit could be used to restrict the torque or detect the shaft being jammed. I don't know about a stepper motor. I think using a DC or AC motor with an encoder, forming a servo system, is the best route to take. It's also possible to measure the back EMF from a DC motor or synchronous AC motor to monitor the speed so an encoder won't be necessary for speed regulation, unless you need to know the exact position of the shaft.

Please post a link to the software you're having difficulty with.