| Author | Message | |||
     FERNY |
will this idea work? converting DC voltage to AC using an oscillator by connecting a 9volt battery to the two terminals of the oscillator then connecting a wire to the terminal on the round side. then connecting another wire to the negative (-) terminal of the battery then you can just connect the wires into something. | |||
| Simon Quellen Field (Sfield) |
Your idea will work fine. You will get a 1 million hertz square wave at approximately 7 volts, and 1/30th of a watt. Don't expect to run electrical appliances that want a 60 hertz sine wave at 120 volts and several watts. The AC current the oscillator produces is not the same as the AC current coming from a wall socket. You could build a 60 hertz sine wave oscillator that produces 120 volts and can supply several watts. Such a device is known as an inverter. | |||
| FERNY |
if i connect a transformer with a 7volt primary and a 120volt secondary to the oscillator would it produce 120 volts at 1 million hertz could it power up something like a alarm clock or would the alarm clock not work cause it has to be 60 hertz | |||
| Simon Quellen Field (Sfield) |
Some old AC driven clocks use the line frequency, but most of them now use quartz oscillators to keep better time. The transformer would have to be able to handle 1 Mhz. A transformer made for 60 hz would not work well at 1 Mhz. Most of the clocks running on AC probably need more power than the 30 milliwatts the oscillator puts out. | |||
| Anonymous |
according to what the other guy said WHY DO capacitors explode??? | |||
| Simon Quellen Field (Sfield) |
Electrolytic capacitors have a liquid in them. If you put too many watts into one, the liquid vaporizes. The capacitor is sealed, so quite a bit of pressure can build up before it splits open. This is why a firecracker goes bang, but will only fizzle if you open it and light the powder inside. | |||
| johny |
I have got a oscillator from a macintosh computer and it says 1.115MHz. the oscillator is color blue and it is like 1 and a half inches high is this oscillator work for the AM transmitter and what is the difference from this one and a the other small one? | |||
| Simon Quellen Field (Sfield) |
Are you sure it's an oscillator? That sounds much too big, and blue is an unlikely color. Does it have four pins? What voltage is it designed to use? | |||
| johny |
It has four pins with one corner sharp and the rest round I'm sure its an oscillator because when I took it off the motherboard the spot were the oscillator was said: 'Oscillator12' Im not sure about the voltage but the computer had a 12volt and 5volt power suppy.I'm not sure why its blue maybe because the macintosh was made in 1978 or something. | |||
| Simon Quellen Field (Sfield) |
Try it with 5 volts and assume the pins are standard. Listen at that frequency on a receiver. | |||
| jesse |
is it possible to build a receiver capabale of receiving radio frequency up to 30GHz? if so what modification would be needed to the three pennie radio if so what can be added or taken away for this kind of frequency? | |||
| Simon Quellen Field (Sfield) |
Planning some radio astronomy? You might want to check out this site. Other places to look might be here or here. Designing for millimeter wavelengths is not easy. You're not going to just modify a crystal radio schematic to do it. A half-wave dipole antenna at 30 Ghz is about the size of the period on this sentence. | |||
| FERNY |
I had built a crystal radio and was wondering if were the crystal earphones are connected could a audion transformer with the 1000ohm side be connected were the crystal earphones were and connect a regular 8ohm speaker to the 8ohm side of the transformer. would this work? would it have enough volume to hear across the room? | |||
| Simon Quellen Field (Sfield) |
That should work fine. The volume will still be low, however. You can make excellent headphones this way. Adding a cone to the speaker (like a megaphone for your mouth) will help direct the sound to the listener, much like the cone on an old Edison phonograph or Victrola. I have a piezoelectric earphone glued to a hole in the small end of a large conch shell, and if the room is quiet and the radio is tuned to a strong station, I can hear it across the room. | |||
| Jesse |
If the tree penny radio cannot be modified to receive very high frequencies can it be modified to receive very low frequencies in the 3KHz range? if it is possible please give links or information on modifiyng the tree penny radio to receive these kinds of frequencies | |||
| Simon Quellen Field (Sfield) |
To modify any AM radio to receive AM signals at any frequency, you can use a downconverter, also known as a transverter. You can search Google for those terms and find circuits and devices. The idea is to take the frequency you have, and mix it with a frequency close to the one that you want. You get a signal that contains the sum of the two frequencies, and the difference between them. The sum is much higher in frequency than the difference, so it is easy for the AM radio to filter it out. The difference frequency is in the AM band, so you can tune the AM radio to pick it up. | |||
| Jesse |
On a regular AM/FM radio to make the frequency lower to the 1800-2000Khz range can a 100pF capacitor be soldered in series with the variable tuning capacitor and the Ferrite Core Coil. Will this work or not? if it would work would I have to solder the 100pF capacitor in series or parallel to the variable tuning capacitor and the tuning coil? by the way your site is awesome!  | |||
| Simon Quellen Field (Sfield) |
1.8 Mhz is a higher frequency than normal AM, not lower. Our Three Penny Radio project is simple enough that you can lower the capacitance by placing a fixed capacitor in series with the tuning capacitor to tune higher frequencies. You would want to use a similar capacitor to the tuning capacitor, not just some ceramic capacitor from the junk box. Commercial radios may have tuned filters and tuned front end amplifiers that would interfere with changing the frequency in this way. | |||
| Jesse |
Its because I got my Amateur liscence and my 1945 ham radio can transmit frequency's from the 1800-4000Khz but the receiving circuit of the ham radio does not work because a valve is broken and cant be replaced so I just wanted to know how to modify a radio to receive the 1800-2000KHz frequency.So it would only work if I add another variable capacitor in series with the other variable capacitour and tuning coil? Or how could I do it? | |||
| Simon Quellen Field (Sfield) |
Putting two of our variable capacitors in series should make the Three Penny Radio tune to those higher frequencies. You could also try using the smaller of the two capacitors (our variable capacitors have three leads, and two variable capacitors in one). | |||
| Jesse |
I got myself a tunable AM/FM radio and a variable capacitor from catalogue and I want to put the varialble capacitor in it to tune higher frequencies. I opened the radio and the variable capacitor had four leds, one on the left and three on the right how do I connect the variable capacitor and which one do I disconnect to connect in series? the vaiable capacitor's left pin(the one alone) has the tuning coil connected, the pin on the top right has the other end of the tuning coil connected, the one in the right midle and right bottom have lead wires connected to the board. How do I connect the other Variable capacitor to the one it already has to increase the frequency? and I want to make the both AM/FM tune to higher frequecies how do i do it? | |||
| Simon Quellen Field (Sfield) |
I can't help you much with your commercial radio. You may be able to make it tune higher frequencies by placing another capacitor in series, but the radio may have other circuit elements that are tuned to the AM band that will foil your efforts. With the Three Penny Radio project on my web site, adding the extra capacitor will work. | |||
| Jesse |
alright ill try that thanks anyway | |||
| Anonymous |
Can a oscillator be modified to increase or decrease the frequency? and if two oscillators are connected in parallel will they transmit a stronger frequency? and another question is the MK484-1 can it be found at radio shack? and how does it work?? | |||
| Simon Quellen Field (Sfield) |
You can build your own oscillator if you want one with more power. Or you can build an amplifier to boost the power of an oscillator. A very simple amplifier is just a CMOS hex buffer chip like the 4049. Just tie all six buffers in parallel and connect the input to the oscillator and the output to the antenna. The MK484 is difficult to find in small quantities. That is why we offer it in the catalog instead of telling you to go to Radio Shack (they don't carry it). It is a tuned radio frequency receiver. It has radio frequency input preamplifiers, and audio output amplifiers, and a detector stage. You can think of it as a crystal radio with an amplifier in front (at the antenna) and an amplifier in back at the earphone. | |||
| Anonymous |
oh, alright. How do I build my own oscillator with more power. Do I need hard to find parts or its simple to build? | |||
| Simon Quellen Field (Sfield) |
Read the book "Radio Amateur's Handbook" by the ARRL. It has all you need. You can find it in any library. | |||
| Anonymous |
what is a Superheterodyne receiver? does it receive high frequencies or low frequencies? | |||
| Simon Quellen Field (Sfield) |
A superhet is a radio design that can receive any frequency. A receiver works by filtering out all but one frequency. It is not easy to make good tuneable filters. It is much easier to make good filters if they aren't tuneable, and only pass one frequency through. A superhet uses a neat trick, where it shifts the frequencies of incoming radio waves in such a way as to bring the desired frequency down to the frequency of a fixed filter. In AM superhets, the fixed filter is usually 455 kilohertz. The superhet "mixes" the incoming radio waves with a local oscillator, resulting in a signal that contains the sum of the two frequencies, and the difference of them. If the station you want to listen to is on 1000 kilohertz, the superhet will mix it with a signal at 545 kilohertz. This results in several frequencies: 455 khz, 545 khz, 1000 khz, and 1545 khz. These are all sent to the filter, which only lets the 455 khz signal through. Other stations, say those at 800 khz and 1500 khz, also get mixed, but the mixing does not result in any signal at 455, so they are filtered out also. In FM superhets, you often find "dual conversion" receivers, which first mix the signals down to 10.7 megahertz, and then down to 455 khz. This extra step helps to eliminate signals that a single step might allow through. Some communications receivers use three or more stages. See this article for more information. | |||
| Anonymous |
will capacitors work better at holding a charge paralell or in series?? also By putting them in parallel will they hold more capacitance or voltage?? Also if I place capacitors of a different type will it decrease performance?? | |||
| Simon Quellen Field (Sfield) |
These questions are dealt with in the section on making a radio out of houshold items. Parallel or series connections have no effect on how fast a capacitor loses charge. That is caused by resistance inside the capacitor. Parallel capacitors increase the capacitance. Series capacitors can be charged to higher voltages than either capacitor alone. Capacitors come in different types for several reasons. Electrolytic capacitors can hold a lot of charge in a small space. Ceramic capacitors are cheap. Mylar, polyester, mica, and other types are selected because they have special properties, such as high voltage tolerance, accuracy, cost, or some other attributes. | |||
| CAN OZER |
What will happen if I connect A.C to the capacitor? | |||
| Simon Quellen Field (Sfield) |
For a parallel plate capacitor like a ceramic or mica capacitor, the capacitor will first charge up to the positive voltage swing, then discharge as the voltage swings negative, then charge up to the negative voltage, and back and forth this way until the power is removed. If the frequency is high, the capacitor may not have time to fully charge, so the voltage in the capacitor will not reach the full voltage applied to it before the voltage swings low again. Applying more voltage than the capacitor is rated for will cause the capacitor not to work. For electrolytic capacitors, reversing the polarity will damage the thin layer of dielectric in the capacitor, and it will no longer work. | |||
| ENGIN ILGIN |
I m an ocean going watch officer and there is a thermistor is used to measure temperature of a telecommunication system on the ship where I m working.The system has been damaged due to overheating and I have been asked to check the instrument and report back but I dont know how to write technical report about it.I will be very glad if you help me. | |||
| Simon Quellen Field (Sfield) |
You might try Google Answers. They have a 100% satisfaction guarantee on this sort of help. | |||
| Anonymous |
I got a Intel Pentium preocessor from a computer. Can it be used as part of a transmitter? and if some pins connected to battery can other pins make a 60/50Hz sine or square wave which then can be connected to transformer? also can some electronic projects be made by using processor? (sorry for misspelling) | |||
| Simon Quellen Field (Sfield) |
Not really. You might be able to use a pair of pins for the diode in a crystal radio, but it would not be as good a diode as a germanium one would be, and it would be a few thousand times more expensive. The processor needs a clock signal to do anything. The clock signal is what the oscillator produces, and a processor is not an oscillator. Some pair of pins may happen to be connected to the input and output of a buffer or inverter that you could bias into linear operation, but I would not know which pins they might be. But then you would still need a crystal or a tank circuit for the feedback loop, and you might as well just buy a $0.30 inverter chip instead of using a $200 processor. | |||
| Anonymous |
Why do hard disk drives have stepper motors instead of regular D.C motors? and also when a computer power supply has a short circuit in one of the wires what is the popping and crackling sound coming from the inside? | |||
| Simon Quellen Field (Sfield) |
A stepper motor is easy for a computer to control. The computer sends a pulse, and the motor "steps" by a degree or so (often 1.8 degrees, or 3.6). This makes it very easy to control the speed, or (in slow drives like floppies) to move the read head to a particular place. The popping sound is the sound of a good power supply becoming a piece of junk, by overheating transistors, resistors, and capacitors. As they heat up, they expand, and the material they are encapsulated in breaks apart. Electrolytic capacitors can explode as the electrolyte boils. | |||
| Anonymous |
On amplifiers if a speaker that is not rated ohmnage can the amplifier get messed up or will it just not work? | |||
| Simon Quellen Field (Sfield) |
If the speakers are not matched to the amplifier, you will get energy reflected back into the amplifier. Whether this causes damage to the final output transistors will depend on the amount of mismatch, the power used, and the transistor and its heat sink. The speaker can be damaged if the power is too high, but that is true of matched speakers as well. A setting that would be tolerated by matched speakers may not fare as well with unmatched speakers, however. | |||
| DUKEofURLs |
I need to boost FM radio reception somehow for a favorite radio station. The existing FM antenna is nothing more than just a wire out of the back of the unit. Any suggestions? Thank-you... | |||
| George L. Unregistered guest |
Simon, regarding the AC/DC topic, you said you can turn DC into AC by using that ocillator, but it has to be a frequency that a transformer can take. Could I do the same if I made an ocillator from a capacitor and a coil (the LC circuit) that ocillates at 60 Hz? Also where would I connect the AC wire(in between the coil and capacitor on both sides?) Thanks in Advance, George L. | |||
| Simon Quellen Field (sfield) New member Username: sfield Post Number: 185 Registered: 12-2004 |
You will need more than a capacitor and a coil to make an oscillator. You need some way to get amplification, usually a transistor. You can also make a transformer that is designed to work with higher frequencies, such as 1 Mhz. This is easily done -- look at all of the transformers used in radio frequency devices, such as the antenna coil in our radio kits (which is designed to work at frequencies between 0.5 Mhz and 2.0 Mhz.) | |||
| George L. Unregistered guest |
So...what you are saying is this will work I just need to amplify the output from the ocillator so it will work with the transformer and I need a transformer for a higher frequency. If I make a ocillator for 60 Hz and amplified it, then it went into the transformer...it would work...right? Also I need to amplify the current right? Thanks, George L. | |||
| Simon Quellen Field (sfield) New member Username: sfield Post Number: 186 Registered: 12-2004 |
No. What I said was that you cannot make an oscillator from just a coil and capacitor. If you have an oscillator that works at some particular frequency, and puts out the power levels you need, you can make a transformer that works for that frequency. | |||
| George L. Unregistered guest |
ok, thanks | |||
| james curry Unregistered guest |
building a shortwave radio, need am air capacitor 40-460/30-156 to finish project. dual gang.econ-oceanic radio i started when this capacitor sold out please help????????? caw24089@yahoo.com | |||
| justine aquino (Mnado) Member Username: Mnado Post Number: 19 Registered: 12-2005 |
can you use any kind of oscillator with four pins to the computer controlled transmitter? | |||
| justine aquino (Mnado) Advanced Member Username: Mnado Post Number: 56 Registered: 12-2005 |
is the electricity coming from the electrical socket ac? | |||
| Angus Chalmers (Fungus) Member Username: Fungus Post Number: 20 Registered: 12-2005 |
You can use any oscillator as long as it is in the AM band. The electrical socket is AC. | |||
| alex (Alex) New member Username: Alex Post Number: 1 Registered: 4-2007 |
George L. If you need an oscilator easy enough to build and realy cheap you might want to consider a Hartley oscilator (see attachment for schematics, open it with notepad(windows) or Kate (un*x)) by tunning the values of the components you get the frequency you want it worked for most of my projects (including a solid state tesla coil)
| |||
| physics boy (Physicsinaction) Intermediate Member Username: Physicsinaction Post Number: 40 Registered: 7-2006 |
How can we make a 220vdc to 220vac converter | |||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 1848 Registered: 12-2004 |
It's called an inverter. You can find schematics using Google. Where are you getting your 220 volts DC? | |||
| physics boy (Physicsinaction) Intermediate Member Username: Physicsinaction Post Number: 41 Registered: 7-2006 |
I have connected several DC batteries in series to get 220 Volt DC I have searched on google but my problem is still there My problem is to get accurate 60 HZ frequency | |||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 1850 Registered: 12-2004 |
What are you trying to power? | |||
| physics boy (Physicsinaction) Intermediate Member Username: Physicsinaction Post Number: 42 Registered: 7-2006 |
I want to power home appliances and sorry about in previous posting I want 50Hz frequency basically I have seen that inverter those which convert 12 volt DC to 220 volt AC lost must of their power in heating and are not efficient so I want to make an inverter which can convert 220 volt DC to 220 volt ac. | |||
| Theresa Simmons (Theresa) Junior Member Username: Theresa Post Number: 8 Registered: 1-2008 |
I recommend you stay away from lethal voltages and currents. Commercial 12 volt inverters can be purchased with 85% and 90% efficiencies. It is very unlikely that you will come up with a design that is more efficient, or be able to build it. Starting with a higher voltage is only important if you have a long distance between the battery and the inverter. Place the two close together, and you will not have appreciable losses. | |||
| physics boy (Physicsinaction) Intermediate Member Username: Physicsinaction Post Number: 43 Registered: 7-2006 |
That is quite a good thing but where I live inverters are available with only 50 to 70 % effeciencies besides I also want to know how it can be done. | |||
| physics boy (Physicsinaction) Intermediate Member Username: Physicsinaction Post Number: 44 Registered: 7-2006 |
That is quite a good thing but where I live inverters are available with only 50 to 70 % effeciencies which are in range that mostly peoples can buy others with greater efficiencies are very expensive besides I also want to know how it can be done. | |||
| Theresa Simmons (Theresa) Junior Member Username: Theresa Post Number: 9 Registered: 1-2008 |
It doesn't matter where you live. Companies that sell inverters on the Internet ship all over the world. "http://www.unipower-corp.com/Unipower_Telecom/Telecom_Product_Line/Telecom_Inverters/YKPSW1000_2000_Inverters/YK-PSW_Inverters.html" "http://www.google.com/search?q=inverter+price" Building one yourself will be more expensive, and much less likely to be 90% efficient. And you are making it harder on yourself by starting with 220 volts -- there aren't a lot of oscillator designs floating around for that voltage. A simple Google search would have answered your question: "http://www.google.com/search?q=inverter+circuit". I'm curious -- what part of the world are you from? Where do they use 220 volts and 60 hertz? | |||
| physics boy (Physicsinaction) Intermediate Member Username: Physicsinaction Post Number: 45 Registered: 7-2006 |
Peoples here don`t use 220 volts inverter this is my idea as i have already told in my previous postings that I think that converting 12volt to 220volt is not efficient anyway thanks for help |
hartley oscilator schematics