Switch to reset charge amplifier

Started by Geoffrey in sci.electronics.design6 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...


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.design3 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.design10 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...


"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...


Photodiode Amplifier Noise Effects

Started by WhiteDog in sci.electronics.design9 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.design3 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.design3 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


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

Started by Phil Hobbs in sci.electronics.design3 years ago

On 05/14/2015 11:52 AM, Felipe Jimenez wrote: > On Thursday, May 14, 2015 at 4:08:04 AM UTC-7, Phil Hobbs wrote: > > > Oh and I'm fairly...

On 05/14/2015 11:52 AM, Felipe Jimenez wrote: > 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... "se


noise in instrumentation amplifier

Started by val in sci.electronics.design1 year ago 24 replies

Hello all, I have a basic instrumentation amplifier made with three MAX 44245 op amps. My problem is that I have too much noise in the 50 to...

Hello all, I have a basic instrumentation amplifier made with three MAX 44245 op amps. My problem is that I have too much noise in the 50 to 100 kHz bandwidth and I don't know how to reduce it. Maybe I don't have enough phase margin around 100 kHz (the GBW product of the 44245 is 1 MHz and the gain of the first stage of the instr. amplifier is about 10). However, the data sheet says that t...


Highly Linear ADC Driver Amplifier - need suggestions

Started by Darol Klawetter in sci.electronics.design5 years ago 20 replies

I'm currently researching the amplifier options for the output stage of a R= F receiver I'm designing. This stage will have a single-ended output...

I'm currently researching the amplifier options for the output stage of a R= F receiver I'm designing. This stage will have a single-ended output and wi= ll drive an ADC that has a SFDR of 100 dB. Of course, I need a highly linea= r amplifier to prevent washing out my ADC performance, but I don't want to = use one with differential I/O, which is typically used to drive high-perfor= mance ADCs...


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

Started by Phil Hobbs in sci.electronics.design3 years ago

On 05/14/2015 11:50 AM, John Larkin wrote: > On Thu, 14 May 2015 04:07:59 -0700 (PDT), Phil Hobbs > wrote: > > > > Oh and I'm fairly...

On 05/14/2015 11:50 AM, John Larkin wrote: > 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. > >


Differential Amplifier is an input stage of every op-amp

Started by Patrick Chung in sci.electronics.design3 years ago

Generally, if input stage of an operational amplifier is realized as BJT tr= ansistor differential amplifier, op-amp has smaller slew rate,...

Generally, if input stage of an operational amplifier is realized as BJT tr= ansistor differential amplifier, op-amp has smaller slew rate, smaller volt= age offset and better CMRR. If it's realized as JFET transistor based diffe= rential amplifier, voltage offset is higher, CMRR is smaller but slew rate = is better.=20 Read more: http://www.cirvirlab.com/index.php/tutorials/167-bjt-tran...


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

Started by Phil Hobbs in sci.electronics.design3 years ago

On 05/14/2015 12:15 PM, George Herold wrote: > On Thursday, May 14, 2015 at 11:57:36 AM UTC-4, Phil Hobbs wrote: > > On 05/14/2015 11:50 AM,...

On 05/14/2015 12:15 PM, George Herold wrote: > On Thursday, May 14, 2015 at 11:57:36 AM UTC-4, Phil Hobbs wrote: > > On 05/14/2015 11:50 AM, John Larkin wrote: > > > 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


Stable simple dc amplifiers

Started by Archival in sci.electronics.design6 years ago 32 replies

I need a simple(=3D cheap) relatively stable(temp and noise) dc amplifier t= hat can take a voltage from 0 to 5V and output from around 0V(not...

I need a simple(=3D cheap) relatively stable(temp and noise) dc amplifier t= hat can take a voltage from 0 to 5V and output from around 0V(not critical)= to near Vcc(but arbitrary) somewhat linearly. I'm thinking a simple bjt amplifier with temp compensation will work decent= ly but the issue is linearity and range. e.g., the output voltage of an ideal CE amplifier is Vout =3D Vcc - Rc...


Problem with audio amplifier

Started by eryer in sci.electronics.design8 years ago 2 replies

Hi, I have a problem with this audio amplifier (i'm new in this field, so excuse me for my...

Hi, I have a problem with this audio amplifier (i'm new in this field, so excuse me for my questions): http://focus.ti.com/lit/ds/symlink/tpa2005d1.pdf I've used it as single ended amplifier. It is connected to a DAC: between DAC and IN- a CR high pass filter is present. DAC can generete signals from 0 to Vdd (the same Vdd of TPA2005); so a value between -Vdd/2 +Vdd/2 is present in IN-. Fro...