Hero999

I can't help you, if you don't answer my question.

No, it's not that simple. A good audio amplifier is designed so its volume is independent of the power supply voltage - a characteristic known as power supply rejection ratio. If the volume is set high, it will stay exactly the same until the battery voltage is too low to give the required peak voltage to the speaker, causing the output signal to become clipped and distorted. In other words, it will sound the same until the voltage drops past a certain point at which the sound quality will deteriorate rapidly. Turning the volume down should improve the sound quality but it will oviously be quieter. If the volume is set very low, the amplifier will become unstable when the battery voltage drops below a certain point. It will either stop working completely, the sound will become distorted or it will oscillate and make a funny noise. Turning the volume down further won't do any good. Did you measure the output voltages of the power supply with the load connected or disconnected? Some poor quality unregulated power supplies give a higher voltage unloaded than when loaded. No, an audio amplidier doesn't require a regulated power so adding one is a waste of time, just connect it to the battery via a fuse with roughly the same rating as the power supply. Or you could read the datasheet before you buy it. If it's a linear regulator, the output will be as specified until the input voltage drops below a certain level equal to the rated output voltage plus the drop out voltage.

How much current does the relay coil use? The TL431 will be fine for small relays <50mA or higher with a transistor.

What do you think? Google for the datasheets and read them.

Please don't post the same thing more than once. The formulae you require are linked below: http://www.nepsi.com/formulas.htm http://www.generatorguide.net/watt-acpower.html http://en.wikipedia.org/wiki/Power_factor

Yes, alternators generally produce quite a clear sine wave.

So it's a diesel generator, not gasoline. From what I've read, only large diesel engines don't have glow plugs but it doen't matter either way as glowplugs are just heaters ant don't produce any electrical noise. All gasoline engines have spark plugs which can cause electrical noise if not suppressed properly but as it's a diesel engine, it shouldn't be a problem. Unfortunately, I don't know where the noise is communing from.

THere shoud be no need for a voltage regulator for speakers which should be fine when operated from 10V to 15V. If you measure the voltage or the mains adaptor powering the speakers, you'll probably find that the voltage is probably higher than 15V.

Please post a photograph of the waveform. Any petrol (gasoline) engine will have an ignition system, even if it has no battery. Diesel engines have glow plugs but no ignition system. An inductor is just a coil of wire, normally wound round an iron core to increase the inductance. Non-polarised capacitors are required for AC. The best solution is to just buiy a ready made mains RFI filter.

It all depends on the required sound quality and how much experience you have. It's possible to use PWM from an MCU I/O port and a low-pass filter to get an analogue signal or build an R2R DAC from resistors but the sound quality won't be great. CD sound quality requires a proper DAC, an MCU capable of managing the 88kB/s of data throughput and addressing the 132MB of flash memory to store all of the messages.

To answer your question: it's definitely possible. You shouldn't need to use 50 ICs, unless you need to play them all at once of course, the data could all be stored on one flash memory device and played back through a DAC. There shouldn't be any need to use an MCU with 50 pins either, multiplexing can be used to reduce the number of pins required.

Have you tried putting the reed switch on the 24VDC side?

I assume you're using 110VAC, the DC is a typo? Even if the steady state current is low, a large current will flow for a short time when the capacitor charges which is probably what's causing the switch to fail.

I don't have the files, mixos posted them, not me.

That's not too bad, it appeard to be EMI, possibly generated by the ignition system, rather than distortion which would change the overall shape of the waveform. A capacitor probably wouldn't do much because the imedance of the generator to high frequencies wouldn't be enough. An inductor in series and capacitor in parallel will be much better.

Try searching for 2SkK608 amd 2SK2545. And please don't spam the forum by posting the same question in several threads. Why did think asking the same thing over and over increases their chance of a helpful? Would you give a better answer if I asked you the same question several times? If so why?

If you look at the Linear Technology, National and Maxim Semiconductor websites (Google them, if you don't know) you'll find a wizard to help you find the correct part. There's also a program which will help you to design the circuit.

You need to have a peak voltage of at least 502V to get 70W RMS into a 180 Ohm load. The amplifier would have to be designed for 63kW RMS into 8R for that voltage. You won't be able to find an audio amplifier with that power level. You could use an impedance matching transformer with an ordinary audio amplifier or build your own amplfier. I don't know what's the best core material to use for 3kHz to 5kHz, it's a little on the high side for laminated steel but is low for ferrite. The Wikipedia article linked below gives the formula for a calculating the turns ratio. http://en.wikipedia.org/wiki/Impedance_matching The minimum number of turns on the primary is determined by the peak flux density the core can handle before going into saturation. This occur under the highest powrer level, at the lowest frequency. HEre are some articles with the calculations you require. THe theory is basicaly the same for any transformer with a magnetic core. http://focus.ti.com/lit/ml/slup126/slup126.pdf http://www.fairchildsemi.com/an/AN/AN-4140.pdf http://en.wikipedia.org/wiki/Transformer http://ludens.cl/Electron/trafos/trafos.html

Does it need to be a sine wave? There are probably cheaper and more effective options such as an h-bridge IC designed for motor control.

Hi welcome to the forum. Please don't make duplicate threads, I deletecd the other thread. Have you read audioguru's detailed explanation of how the circuit works?

A Reed switch is too slow. A MOSFET is probably the best solution but the inductor will need to have a supressor diode fitted. How do you plan to generate the 250Hz signal to drive the MOSFET? A 555 timer can be used but it needs a lower voltage power supply. You could use the LM317 to generate 12V to power the 555 but it has a maximum input-output differential of 40V so you could use a series resistor in addition to it, to reduce the voltage.

Try the 2SK940. Have you tried tracing the PCB and reverse engineering the schematic?

TDA7052 Datasheet linked below: http://www.kitsrus.com/projects/tda7052.pdf

I thinkyour best bet is to reverse engineer the circuit. If you bodge something together yourself and it doesn't properly stun the chickens, you could have the animal rights people on your back.

Are you sure the voltages are the same? I'd just buy a new adaptor or cur off the 3.5mm jack and replace it with a micro USB. This will only work if the voltage is the same and the new satnav doesn't use more current.