[Hard wire media device into car?]

Is that with the engine running?

That's quite low and would indicate a flat battery.

Try it, a lower voltage shouldn't do any harm. It might just become unreliable.

[Hard wire media device into car?]

It should be possible to wire the DVD player directly to the car without and other circuitry.

[Help Me Decide]

I don't know. All I can say, is if you want Rigol, don't bother with the DS1102, get the DS1052E  and hack it to 100MHz.

[Multiturn loop antenna design]

24Hz? Are you sure you don't mean 24kHz?

24Hz is far too lower frequency to be of any use. You'd need an enormous antenna. The wavelength is 12491km which is the approximate diameter of the earth.

[mpu6050 dmp]

Sorry, I've no idea so can't help you.

[mpu6050 dmp]

What do you mean by dmp? Have you searched for the datasheet using a search engine?
http://www.cdiweb.com/datasheets/invensense/PS-MPU-6000A.pdf

[High Power invertor circuits]

Read the papers linked below:
http://www.wpi.edu/Pubs/E-project/Available/E-project-042507-092653/unrestricted/MQP_D_1_2.pdf
http://www.ti.com/lit/an/slaa602/slaa602.pdf
http://www.wpi.edu/Pubs/E-project/Available/E-project-042711-190851/unrestricted/PWM_Techniques_final.pdf

[Need help understanding a technical spec]

It's per die.
http://docs-asia.electrocomponents.com/webdocs/0f86/0900766b80f86647.pdf

[How this ps unit works??]

A center tapped transformer is perfect for producing a negative dc supply voltage. This one doesn't have one.

This circuit uses a bi-phase rectifier. Each diode acts as a single phase rectifier but the AC voltage applied to D2 is 180^o out of phase, thus full wave rectification is achieved.

[Hi, somebody help me. (transistor)]

Sorry we don't do email here because it defeats the purpose of a forum. If you want to do email, join an electronics mailing list.

[QUESTION SOLAR PANEL AND POWER]

Measure the battery voltage.

Your drawing doesn't show how the batteries are connected or the solar cell voltage. The battery voltage could be 12V, 24V, 36V or 60V, depending on how they are connected.

[Coupled output inductor design]

I don't understand the question.

Generally, you don't worry about the inductance of the secondary coils. Wind the primary for the desired inductance, then wind the secondaries based on the turns ratio, rather than the inductance.

[pc fan control by temperature]

There's no resistor between the output and adj pin. Normally 120R is recommended but as it's possible you'll be able to use a higher value as the fan will provide the required minimum load.

[UV curable solder mask]

No, it won't just dry up.

UV light is needed as a catalyst to cure it.

[Inverter oscillator]

Although the oscillator will normally work with two gates, it may fail to oscillate if C is small.

A three gate oscillator is more reliable.
http://www.fairchildsemi.com/an/AN/AN-118.pdf

[Inverter oscillator]

You can make an astable multivibrator with TTL but you need to use lower value resistors and higher value capacitors, as the input impedance is low.

[Programming cameras to detect patterns]

It requies a fair amount of processing power so you need a computer, not just a little microcontroller.

A Raspberry Pi with the appropriate image recognition software (there are probably some free/open source programs for this) is probably the cheapest/easiest ay to do this.

[Help with voltage conversion]

It's fairly straight forward.

The input voltage range is 2.75-0.55 = 2.2V

The output voltage range is 5 - -5 = 10V

The gain is 10/2.2 = 4.545V

[Electric Fan Relay Switch]

The PWM from the controller should be enough to light a small LED but its brightness will vary, depending on the speed of the motor.

[12V, 5V, 3A dual power supply based on the LM2596]

Simply use any PC SMPS. One will get all these voltages.

No.

A PC SMPS is designed for 100V to 250VAC input. He needs to run it off 40VDC.

[Audio Switch Help]

Yes for stereo, you need separate switches for each channel.

[EL Wire Project]

EL wire typically requires about 90VAC to 150VAC at 200Hz to 1kHz to light. A bug zapper produces over 5kV.

Your best bet is to buy an inverter specifically designed to power it.

[PC Heat Alarm Circuit Help]

Wow what a complicated way of doing it. Rather than a CA3130, two 555s and a speaker, I'd opt for an LM393 and a piezo buzzer.

Have you tried testing the astable part of the circuit separately?

[7912 as negative voltage regulator issue]

Hee, hee.
I did not notice that the supply polarity was backwards.

Lol what amused me is he wasted 5 regulators without realising there was a problem with the circuit.

The lesson is, if it gets hot and components smoke, check there's nothing wrong with the circuit before replacing them and trying again.

Here's how to do it correctly.

[What do you think about a new do it yourself e-paper display kit?]

It seems like an interesting concept.

The PDF you've posted contradicts itself. The specification says it's capable of driving 24 segments, yet the example in the photograph shows a display with 30 segments.