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98 Threads found on Audio Transformer
I have a need for a programmable voltage source 0-240Vrms (60Hz). The load will be > 500kΩ resistive I have a HP33120A signal generator, that I will use as the PC controllable sinewave generator. I'm wondering if I can use an amplifier like this:
Most audio amps do not have a regulated power supply voltage. They simply use a large enough mains transformer, rectifiers and a large filter capacitor. The DC voltage normally rises a little when the amplifier plays quietly or idles then drops a little at full output power. The little voltage fluctuations are ignored by the circuit.
If you do not have the main current conductor through the centre, just apply a high frequency audio voltage to the connections. The actual inductance will have a high impedance leaving the resistor to take the current. I would do it at several spot frequencies to insure you get consistent results. Say 2KHZ, 5 KHZ, 10 KHZ. Frank
If your electricity is 120V then its peak is 170V and the full wave bridge rectifier drops it to about 168VDC. You need a transformer to isolate it so that if its ground is at 120V instead of 0V and you touch it and touch something that is grounded then the isolation prevents you from dying with a severe shock. If you make an audio amplifier wit
Hi I would like to build a small monophonic audio amplifier that will take audio from the cd player and will be able to drive a transformer, which in turn will AM modulate the anode of a small 8W transmitter. Since audio quality is not too important I wonder if a class-C amplifier is ok, or it has to be AB? I am looking (...)
You are looking for a mains transformer, not an audio transformer. I would try to find a standard transformer with two secondary windings, 15 - 17 volt, 30 - 40 watt.
well, yes, you always have some power being used by the control circuit, so eg in an offline SMPS typically its gets started up by a linear regulator, and then when up and running, some power is often derived from a bias winding on the transformer, for the purpose of powering the control circuit, but its not really like a class a audio amp which c
The transformer will be cooler. The DC will drop more at high currents. Might be audible in audio circuits. The line frequency effects the transformer and the smoothing caps.
Hello , i want to build this stun gun based on ne555 : 116175 I did not find the bd679 and the audio transformer , can i use bd537 instead of bd679? and the transformer i have 220 to 9v centered tape step down transformer , her impedance is 1.2 k primary and 5 Ohms secondary : [ATTACH=CONF
I had audio transformers made by Hammond and they interleaved the windings for excellent high frequency response. The small extra cost was worth it because cheaper ordinary transformers produced poor high frequency response.
Ohms law tells you that you need a higher power supply voltage than 14V, presuming you don't consider a bulky audio transformer. All recent car audio systems have DC/DC converters for this reason.
audio amplifiers have not used an output transformer for at least 50 years. A transformer was used to match the high output impedance of vacuum tubes to the low impedance of a speaker. A modern audio amplifier has an extremely low output impedance so it is a voltage source that drives a speaker directly. The output (...)
audio transformers undergo the same laws as mains transformers. If you understand the basic formulas how voltage, current and impedance gets transformed, you can calculate most aspects of your audio transformer. Two special points should be mentioned: - low frequency full power limit The ability of a
If you talk about matching first requirement is that audio source must have 8ohms output impedance and second is that transformer must be terminated with 1k. What is your audio source output impedance?
audio transformer insulation is not suited for very high voltage maybe a few kV . You can get far better results with a small auto ignition coil. 30kV for example. Energy out will not exceed what you put in e.g. E=1/2 L I^2 * t
Hello I have found this audio video modulator. The author states that it works ok without using an audio transformer. Can it be done or is it hoax?
Hi i build a audio amplifier using LM4440 problem is there is a huming sound comming out from the spekr...when i touched the ground line while my feets are in the floor the noise is can i solved the problem????pls hlp me..thnks.
Hi, I have recently built an audio power amplifier with TDA2050. The project found on this web site originally uses three TDA2030 integrated amps: Circuit Power audio Amplifier with TDA2030 2.1. Following some advice in the comments, I simply rep
...Another thing is to know that iron core is more flux attractive or ferrite core? Selection of core material depends on range of signal frequency. If applied on low frequency ( mains, audio ) the best choice is iron, but above some KHz ( particularly on power switching ) ferrite becomes best suitable. +++
Hello, I have a toroidal core biased to a point using a big number of turns. I need to find the best way to induce an audio signal to the core. An initial thought was to use a capacitor connected to the audio source and the one end of the DC coil, to block DC back to the audio source and to pass the signal through the DC coil. But the DC (...)
I think your lecturer has combined two different problems. For audio frequencies you can use any class of amplifier you want, they can all work to the same specification, some classes are extremely inefficient i.e. 20 watts in for every watt out, so the amplifier gets hot and needs some method of getting rid of the heat - fans and big heatsinks.
If the transformer is operating within it's specified operating limits, then yes, the output voltage is quite linear with respect to the input voltage. audio transformers, for example, can have very low distortion over a wide frequency and voltage range.
30 years and older audio equipment used them. A portable transistor radio/tape player from that age may have the driver and the output audio transformers. Bigger ones on tube audio equipment. But depending what you want to do with it, a plain power transformer can be used.
Hi all, I am trying to build the energy harvesting circuit from the following pdf : is a energy harvesting circuit for extracting power from the audio jack of a phone The trouble is that i cant find th
The higher the frequency, the smaller the transformer. It's easy to find transformers for audio frequencies and they can be tiny. Any oscillator would work, even something based on a 555 timer. JP
transformers vary too much. What kind of transformer is giving you trouble? Mains? audio? Output? Interstage? RF? Not all are designed in the same way. The technology is different too... Be more detailed!
Hi, I am trying to use a Class D Amp to drive a non-audio application (360 - 12000Hz, load will vary), and am getting distortion on the output when no load or lighter load is present. The basic flow is: Class D Amp -> LPF -> Step Up Xfmr -> Output I am using the LPF in the Eval kit (Max9737). The LPF is designed for an 8Ω load
Hi. How many of you have encountered the audio whistle comming from transformer & filter inductor of switching power supplies that they have designed. What do you do to remove this audio noise. As an example I think I would use varnish in the windings for that. I also think that if pwm chip is forced to give clock every cycle and in low (...)
Hello treez, what is cheaper is not the question. SMPS make trouble with noise. A good audio designer will never use SMPS, because he can not calculate the trouble. For myself I have try to develope a sound Mixer and the amp with SMPS first. After the first test I have put the SMPS in trush because of so much noise. This SMPS was an industrial
We know that audio frequency transformer are used for Impedance matching in Amplifiers to convert high impedance to low impedance. Therefore its input and output coils turns are not same. Does it mean it also steps down the input voltage? Secondly, does impedance of audio frequency transformer consist of purely dc (...)
1. You could use a simple audio transformer for the isolation. Jensen transformers manufacturers very good devices for that purpose. See more: 2. If you need more output power, you'll need a simple amplifier. A suitable IC could be LM386.
Hello BradtheRad, all you write is ok for someone in school or university, who has to do an examination, but it isn't good in practice. For real work you don't need exact voltage. You know, that the line voltage is not constant. Here in Europa the line voltage can vary between + and - 5%. So the output can also vary in the same value. If exact vol
I see many schematics that omit R2-R3-R4. I believe the LM1875 is one of those audio IC's that provides its own internal bias network, to lift the non-inverting input to supply_V/2. Also is C8 oriented at the proper polarity?
It is a design of audio amplifier based on well known LM3886 with original effect of ?Magic Eye? on the front panel. Main power supply consists of a 150VA transformer; 2x23V + 6,3V additionally winded, 4x4700uF MKT, bridge 10A
Analog optocouplers are a principle option. High performance analog isolation systems ("isolation amplifiers" are using modulation/demodulation or AD/DA conversion). transformers are still the standard method for high quality audio isolation, and also the cheapest way for low and medium quality.
For matching in this situation you can use a small audio transformer. Where the Turns Ratio of the transformer = SQRT (Load Resistance / Source Resistance) in your situation we can consider: TR = SQRT(32/50) = 0.8 As an example, if the transformer primary winding have 100 turns, the secondary winding must have 100 x 0.8 = 80 (...)
The system consists of velleman K2655 kit, audio amplifier on TDA2003 bridge and motion sensor with a relay that activates the system. The whole is powered by an old transformer TS40. 12V voltage after rectifying gi
You need the frequency of the 10mV -200mV input signal. This needs to be 50Hz in order to use a mains transformer . As such ,it is advisable to use a CAR audio amplifier to amplify from microphone input . The Loudspeaker output terminal is used to drive any relay with 12VDC coil voltage .
I have a little project that I am working with that is beating me at the moment and I thought an audio transformer could help me but alas no. From what I understand (now) is that any short circuit on the secondary side of a transformer, will be a short circuit on the primary due to induced flux across the transformer. (...)
Hi my simple yet confusing question (at least to me) is, can audio transformer with 600 ohm primary and 600 ohm secondary winding be used in 50ohm primary 50ohm secondary circuit ? little about back ground, I have to tx/rx data over 30 to 50 ohm coaxial cable using interface that is actually designed for 600 ohm line. I will change op amp out
A mains transformer is designed for 50Hz or 60Hz and some work poorly at 6kHz. audio transformers with good high frequency response are bifilar wound. Your PWM frequency is low enough to be very audible and causes the filter to be poor. Manufactured pure sine-wave inverters use a much higher frequency that cannot be heard and a small (...)
Thanks to audioguru, chucky and FvM. In india i have seen that the amplifier named AHUJA, designing pushpull amplifier(for PA upto 1000W) with output transformer.
I need a DC-DC supply that would be for 12-14v input and has around 50vdc output and it needs to be high current. I know they are PWM regulated usually, but some are unregulated. I have found plenty of stuff on PWM supplies and have even tried modifying some for high current with no luck. Does anyone know anything about something like this? It seem
this circuit what is the purpose of using audio transformer ?
Your own audio isolator
I have an audio transformer that is rated on the datasheet with primary at 3.2 ohms and secondary at 1.2Kohms. I use it at 100Khz and it works fine. The thing is how can I work out the power on the primary. I can't accurately measure current because my multimeter seems to change measured current by a lot, lets say 0.4A. So I can only accurately mea
....or a push-pull audio output transformer. Can you post a photograph? Brian.
HI, Just a simple query. Is it a common practice to switch the transformer in the microphone audio speaker(ie getting one with more wire turn) if you want to have a louder volume? Have heard over a small talk with an engineer designing communication system. I have always thought this might introduce more inductance which most engineer do not
Use the attached modulator topology and you don't have to care about audio transformers.
my end goal is 50 volts at 12 amps for a class-D audio application I would like avoid any heavy Iron and Copper in the whole design. so I was thinking of using one of Vicors FARM modules that cleanly filter the AC in and ( possibly are doing sync rectification ) but anyway they put out a 400 volts DC at 700 watts and give a logic out for