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99 Threads found on edaboard.com: Audio Transformer
A capacitor across the signal would normally cause a reduction in high frequencies because of the time it would take to charge and discharge it through the 15K series resistor but I suspect it is there to resonate with the inductance of the transformer primary and cause a peak in response somewhere at the top of the audio range. The 1K resistor acr
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:
Hi there I made this power supply but I haven't tested with load. I've ordered class d audio module but its not shipped yet. I need to wait 2 more weeks. I measured +-50V without load at all. Please tell me, I need to know what will be the voltage with 150W load since there are no regulation. Im wondering. :bsdetector: The sch consists of 5A
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.
The original circuit used an audio transformer that works perfectly at the fairly high frequency used. Your low frequency mains transformer might not work at the high frequency. The slow mains diodes also might not work at the high frequency. The simple circuit might stun a mosquito, not a person. The original 8 ohms to 1k ohms (...)
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?
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!
What is F+ and F- in your CRO display? What is the wave form into the transformer? - is it a proper audio transformer or just a mains transformer?, does this effect show it self at low frequencies?. I see the load is given as 4K, what is the reflected load into the amplifier? does the amplifier work OK straight into a 8 ohm (...)
The audio noise problem that I have observed practically in designs is common with ICs like UC384x series and SG352x series. However new chips like NCP1200 have addressed this audio noise problem with some genius internal design. Stable switched mode operation at low load can be achieved with the said controllers, too. Most produc
Do you believe, as i do, that the audio business uses noise as an excuse to avoid using SMPS, becuase they find mains transformers easier to design and maintain the design thereof.? Sounds queer. Why would anybody need an excuse not to use SMPS? For guitar amplifiers that come in a large case to "carry weight" there's no particular
Who uses AF transformers these days ?? Curious to know. 100 V audio distribution systems are still used in buildings as far as I'm aware of. They involve voltage step up at the amplifier (at least if it'a a transistor amplifier) and step down at each speaker. Micropho
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.
Since 40 years I work in developing and constuction of audio devices. Never I caculate PSUs like you do only in University. I never get problems with the PSU. Please consider that an amplifier not every time must give full power, so that the supply voltage goes up and down. So only have a look that your reservoir capacitor h
You could suppress the bass, but that may sound pretty awful too. The real issue could be the power supply, or your speaker (it is in an enclosure, and is it a single loudspeaker or with a woofer and tweeter)? You may need to read up on audio and speakers, to decide how you wish to improve it. Or, just keep the volume low. If you want to suppress t
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. (...)
a rewinded audio transformer with about factor 3.5 less turns and respective higher wire gauge is feasible of course. I used to make these devices as a school boy. Support it.
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.
Car audio power supply example : Switchmode Power Supply For Car audio The rest of the site has quite some interesting stuff on amplifiers... If you look only for +50V, you can use a simpler implementation like a BOOST converter. The advantage is that you don't need a transformer, but only a simpler s
this circuit what is the purpose of using audio transformer ?
Your own audio isolator
The specification seems to fit an ultrasonic rather than an "audio" transformer. Or perhaps audio for bats... I don't understand, what's the meaning of the said 3.2ohm/1.2kohm specification. Is it a winding DC resistance (possibly) or a nominal load impedance? In any case, it doesn't say anything about rated power. Rated current (defined (...)
....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.