[?] Microphony in op-amplifier.

Started by David Chapman in sci.electronics.design8 years ago 5 replies

Hi, An audio amplifier for telephone speech in the range 300Hz - 4KHz which I've built using parts of a quad-op-amplifier (MC33179), is...

Hi, An audio amplifier for telephone speech in the range 300Hz - 4KHz which I've built using parts of a quad-op-amplifier (MC33179), is suffering from microphony. When listening to the output of the amplifier (with no signals present) and tapping or gently scraping the IC and adjacent components with an non-metallic rod, each tap or scrape can be clearly heard on the output line....


Switch to reset charge amplifier

Started by Geoffrey in sci.electronics.design5 years ago 19 replies

Hi there I have a charge amplifier, used to amplify the signal from a piezo electric transducer, with 2nF of reference capacitance shunted...

Hi there I have a charge amplifier, used to amplify the signal from a piezo electric transducer, with 2nF of reference capacitance shunted with 1GOhm. I need to be able to reset the amplifier, preferably with a solid state device (the circuit has to be very compact, and operate in a high-vibration environment). One possibility which comes to mind is to simultaneously short the amplifier ou...


Power amplifier

Started by Efthimios in sci.electronics.design9 years ago 20 replies

Hi I want to connect a 3800W@8ohms audio amplifier to 4.3kOhms load. Is the output power of the amplifier for 4.3kohms about 7W??? 1....

Hi I want to connect a 3800W@8ohms audio amplifier to 4.3kOhms load. Is the output power of the amplifier for 4.3kohms about 7W??? 1. Also if output power is 7W, is the output voltage of the amplifier Vrms = sqrt(7*4300)= 174 Volt??? 2. Is the above calculations correct or the load is too big for an audio amplifier and it will do nothing??


Pops in audio amplifier

Started by fasf in sci.electronics.design8 years ago 6 replies

Hi, i have a little question about pops in audio amplifier....this is the datasheet of AB...

Hi, i have a little question about pops in audio amplifier....this is the datasheet of AB amplifier http://focus.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=tpa6203a1&fileType=pdf and this is my circuit: 1. TPA6203A1 in single ended configuration (Figure 30 of datasheet) 2. Ri=22K+-1%, Rf=44K+-1% 3. Ci=47nF+-10% I have problems when amplifier is switched off with shut...


Re: high voltage amplifier with wide frequency range

Started by Helmut Sennewald in sci.electronics.design9 years ago 10 replies

schrieb im Newsbeitrag news:90fb8cbb-847f-4f5f-afac-09fbf758af0b@f24g2000prh.googlegroups.com... > Hi, > > I have to design a high...

schrieb im Newsbeitrag news:90fb8cbb-847f-4f5f-afac-09fbf758af0b@f24g2000prh.googlegroups.com... > Hi, > > I have to design a high voltage amplifier, that should amplifiy a 3Vpp > sinussodial signal up to 300Vpp. Furthermore the amplifier should work > with linear phase over the whole frequency range from 100kHz to 4 MHz. > The load of the amplifier will be a capac


Audio Amplifier

Started by eryer in sci.electronics.design8 years ago 1 reply

Hi, I have a little question: in practically all circuits that i have seen, two voltages are present 1. 3.3V used for DAC 2. 5V used for audio...

Hi, I have a little question: in practically all circuits that i have seen, two voltages are present 1. 3.3V used for DAC 2. 5V used for audio amplifier (in Bridge-tied load configuration) Why?Is not possible to use the same voltage (3.3V) for DAC and amplifier? I don't think it is strictly related to speaker volume...or not? Thanks


Antenna Amplifier Noise Figure

Started by rickman in sci.electronics.design2 years ago 88 replies

I read this post in an antenna group and I don't get how this guy is coming up with a negative noise figure. Looks to me like he is...

I read this post in an antenna group and I don't get how this guy is coming up with a negative noise figure. Looks to me like he is calculating the noise figure of a resistor, not the amplifier. Anyone care to explain this to me? The part that seems bogus is this... > The negative NF is defined as the amplifier noise being less than the > increase in noise due to the amplifier gai


Op-amp differential amplifier

Started by Patrick Chung in sci.electronics.design2 years ago 6 replies

Op-amp differential amplifier has much wider range of input signals comparing to differential amplifier with discrete components. Read...

Op-amp differential amplifier has much wider range of input signals comparing to differential amplifier with discrete components. Read more: http://www.cirvirlab.com/index.php/tutorials/170-op-amp-differential-amplifier-simulation.html and also simulate: http://www.cirvirlab.com/simulation/op-amp-differential-amplifier-online.php


10W amplifier, 2.2-2.4GHz

Started by Joel Koltner in sci.electronics.design9 years ago 10 replies

Anyone have an off-the-shelf 2.2-2.4GHz amplifier they like? ~10W is what I'm after. Mini-Circuits has their ZHL-30W-252+ which would be fine,...

Anyone have an off-the-shelf 2.2-2.4GHz amplifier they like? ~10W is what I'm after. Mini-Circuits has their ZHL-30W-252+ which would be fine, although at $3k I'm continuing to do a bit of searching... (And before anyone asks, no, I'm not building a high-power WiFi amplifier and, yes, I do have the appropriate FCC license to put this thing on the air -- with various restrictions on t...


need help explaining amplifier noise levels

Started by IAN in sci.electronics.design9 years ago 1 reply

I am working with an amplifier used in research. The noise level specifications on the amplifier are listed as:

I am working with an amplifier used in research. The noise level specifications on the amplifier are listed as:


"Efficient" audio amp selection

Started by Don Y in sci.electronics.design6 years ago 24 replies

Hi, I've been designing a "network audio client" (aka "network loudspeaker") and now have to select a suitable amplifier to use in it. 1)...

Hi, I've been designing a "network audio client" (aka "network loudspeaker") and now have to select a suitable amplifier to use in it. 1) The amplifier's presence is "optional" (e.g., when interfacing to external equipment via a "line out", the amplifier is superfluous) 2) The design is intended to support one or two audio channels (e.g., drive a single speaker -- BTL? -- or a pair WH...


Amplifier Question

Started by Bob....@gmail.com in sci.electronics.design8 years ago 10 replies

http://www.schematicheaven.com/mesaboogie.htm Pick an amplifier. I'm trying to figure out what the circuit that "surrounds" the reverb circuit...

http://www.schematicheaven.com/mesaboogie.htm Pick an amplifier. I'm trying to figure out what the circuit that "surrounds" the reverb circuit is doing. This is usually the tube section V2 with the reverb tubes being V4 and phase V5. The input and drive are V1 with the FX loop V23. Actually I have a mesa amplifier and I am wanting to have a hard bypass for the reverb and fx loop. There r...


Current source in front of JFET Input Amplifier

Started by wolti_At in sci.electronics.design9 years ago 1 reply

Hello, I am currently working on a prototype for the second generation of an electrode amplifier. It is used to amplify the signals of pH...

Hello, I am currently working on a prototype for the second generation of an electrode amplifier. It is used to amplify the signals of pH and ISE electrodes where the former ones have a very high output resistance in the 100-1000megaohm range. The input amplifier I am using is based on two matched JFET fets in a source follower configuration. The second JFET is used to get a zero DC offs...


Photodiode Amplifier Noise Effects

Started by WhiteDog in sci.electronics.design8 years ago 10 replies

I have been playing with my shiny new photodiode amplifier (BW=75MHz A=35k) and my trusty spectrum analyzer set to 'noise' mode. I'm dissecting...

I have been playing with my shiny new photodiode amplifier (BW=75MHz A=35k) and my trusty spectrum analyzer set to 'noise' mode. I'm dissecting the thing to try and find areas where some simple tweaks might improve the SNR. The photodiode is a 500um PIN device with a NEP of 0.008pW/RtHz and a dark current under -5V bias (on the anode) of about 1.25nA. The amplifier circuit under examinat...


glasselectrode input amplifier

Started by wolti_At in sci.electronics.design9 years ago 17 replies

Hello, I am currently working on a design where I need to amplify the signal generated from a glass electrode and a reference electrode....

Hello, I am currently working on a design where I need to amplify the signal generated from a glass electrode and a reference electrode. Right now I have a basic input amplifier with an instrumentation amplifier from analog devices working. The challenging task on these designs is the very high output resistance of the glass electrodes (up to 200Meg) and the noise immunity. The input sta...


Opto in amplifier screws up output

Started by Fibo in sci.electronics.design2 years ago 21 replies

Hello, I'm trying to make a voltage controlled amplifier. I only need a gain of about 11 max. So I thought I would use an opto as a variable...

Hello, I'm trying to make a voltage controlled amplifier. I only need a gain of about 11 max. So I thought I would use an opto as a variable resistor on an inverting amplifier. I went with the H11F3M https://www.fairchildsemi.com/datasheets/H1/H11F3M.pdf I built up the Automatic Gain Control circuit in the datasheet. I used a 50k resistor as my feedback resistor. When I fired it up, my...


Re: Why Adding a Voltage Amplifier after a Transimpedance Amplifier reduce BW? Book Claim by 0.64

Started by Felipe Jimenez in sci.electronics.design2 years ago

On Thursday, May 14, 2015 at 4:08:04 AM UTC-7, Phil Hobbs wrote: > > Oh and I'm fairly certain the non-inverting amplifier is wired up...

On Thursday, May 14, 2015 at 4:08:04 AM UTC-7, Phil Hobbs wrote: > > Oh and I'm fairly certain the non-inverting amplifier is wired up correctly. Between > > switching back and forth from the non-inverting to the inverting configuration > > several times, I am fairly certain that both configurations were wired up properly. > > Hmm... "several times" does make it sound like a


40MHz Amplifier.

Started by jim in sci.electronics.design8 years ago 27 replies

Hi All, I=92ve built a 40MHz amplifier based on a BLF177 RF FET. The circuit is similar to the 108MHz class B example presented in the...

Hi All, I=92ve built a 40MHz amplifier based on a BLF177 RF FET. The circuit is similar to the 108MHz class B example presented in the datasheet, except I have recalculated the input/output matching networks for the lower frequency. The amplifier works to a point, but performance is poor. With Vds=3D50V Idq=3D0.1A and 1W input I get about 10W of output power, this is far lower than the 20d...


Re: Why Adding a Voltage Amplifier after a Transimpedance Amplifier reduce BW? Book Claim by 0.64

Started by John Larkin in sci.electronics.design2 years ago

On Thu, 14 May 2015 04:07:59 -0700 (PDT), Phil Hobbs wrote: > > Oh and I'm fairly certain the non-inverting amplifier is wired up...

On Thu, 14 May 2015 04:07:59 -0700 (PDT), Phil Hobbs wrote: > > Oh and I'm fairly certain the non-inverting amplifier is wired up correctly. Between > > switching back and forth from the non-inverting to the inverting configuration > > several times, I am fairly certain that both configurations were wired up properly. > > Hmm... "several times" does make it sound like a so


10 W Audio Amplifier Constructional Project!

Started by Yuki in sci.electronics.design6 years ago 6 replies

this 10 W amplifier is very simple yet effective! to view the schematic diagram and components needed to build it, please visit the link:...

this 10 W amplifier is very simple yet effective! to view the schematic diagram and components needed to build it, please visit the link: http://electronicsimple.blogspot.com