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88 Threads found on edaboard.com: Audio Transformer
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?
Maybe your 7812 regulator IC does not have an input voltage high enough, 14VDC minimum? Then the transformer must be at least 12VAC. The output of a properly working 7812 has no hum. This amplifier circuit has an extremely high gain of 700 times so a tiny input signal will be produced at its output. Then using a shielded audio input cable is very
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 (...)
Your teacher was teaching about transistor audio amplifiers made 58 years ago. Here is a low power (only 50mW) transistor amplifier made by Philips in 1955 that used a transformer to match the fairly high common-emitter output transistors to the low impedance speaker. Since the transistors were all PNP germanium ones the battery polarity is shown
It appears this is a power transformer. Therefore it is designed to operate at power line frequencies (50Hz or 60Hz). It will not behave like a broadband audio transformer, in case you were planning on using it that way. As for the 500 ma. current specification, that looks like it is a specification for the 12 VAC windi
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
Hello, the other night my Panisonic TV turned off. Now once it is on, I get audio just fine but no picture, only primary colors (no lines at all). Does anyone have a service manual or suggestions on how to fix it? Thanks!
To achieve high dynamic, an audio transformer needs a magnetic shield, typically a box made of a high permeability material, e.g. "?-metal". If your device hasn't an effective shield, it can't be used in an enviroment of interfering AC magnetic fields. The most severe problem are mains transformers, but I guess pulsating ground currents (...)
If the said radio shack transformer actually has 1:10 windings ratio (unfortunately I don't see a specification at Radio Shack) it most likely doesn't work in your application because of it's expectable high leak inductance. But you should try yourself. Simply consider an about 10 to 20 kHz cut off frequency for usual cheap audio transformer
houseing housing comes after micro HIFI audio system by thomson, I can't exacly remember model, it was something like cs-97 power to amplifier 70W, I used transformer 160VA +/-27V , after rectify is about 35-36V and it is perfe
The first link will not work, it is for isolating audio loops but not ones on a phone line. The second device plugs in-line with the handset of the phone so the phone still needs to be present and you still need to lift the handset to enable the audio. Perhaps this is what you want? Brian.
The two wires of a telephone line are balanced so that each wire has the signal out-of-phase to cancel hum pickup. Your circuit grounds one wire of the telephone line which causes the other wire to act like an antenna that picks up all kinds of interference. Usually an audio transformer is used to keep the telephone line balanced and it also is
hello, i am using sim300 based gsm modem.i want to interfac gsm audio with pc.i have handset connector and through 1:1 isolation transformer i connected it to pc. i am able to hear the audio played in the pc thorugh phone but unable to interface with microcphone,some humm noise is coming.how can i perfectly interface with microcphone.
The secondary of the transformer T1 together with the parallel capacitor resonates on the subcarrier audio channel (depending by the standard, on 4.5, 5.5 or 6.5 MHz). If use the circuit only for video transmission (no audio), you can remove T1, Q3 and adjacent components.
Sinusoidal? You mean to drive the mosfets 'analog' like in an audio amplifier? Normally the 2 N-ch mosfets are connected to ground with the sources. The centertap is connected to the positive supply. Each mosfet willl pull the transformer winding to ground one by one.
plz i want to know the types of the small audio transformers and how to know the ratio bet secondry and primary coils