1. xenon_eleven

    Active Butterworth Bandpass Filter unexpected peak

    I am currently trying to design a bandpass filter in a simulator for a university assignment to the following criteria: Frequencies below 1KHz and above 250KHz should be attenuated. Note that you will need to calculate the cut off frequencies given the pass band (1KHz to 250KHz) should not be...
  2. 8

    Gate Driver vs Opamp

    Hello, I build an RLC circuit using the MCP1402 as a gate driver. At resonance the MCP1402 will drive a 20 ohms load (plus 3 ohms which is the DCR of the coil). Unfortunately the MCP1402 has around 12 ohms output impedance (according to this) and so it cannot drive the load effectively. A more...
  3. C

    Using audio LC filter circuits instead of RC.

    I'm designing a small mixer and stopped at the equalizer section when I recalled the number of small inductors (axial and SMD) in my parts kit. If you search 'filter circuits' or similar you'll ALWAYS get the standard RC topologies, and I'm thinking more of IC feedback types than the usual...
  4. H

    A current-source LED circuit with an op amp

    Dear Team, Please see the attached image which shows the circuit of driving LED using an opamp. We are fixing current through LED using opamp. I am clear about how they obtained the current equation.Isense=Vin/Rsense because opamp is in negative feedback My question is why they are not...
  5. R

    Op-Amp Voltage Follower Outputs ~+Vcc when IN+ is 0V

    Hi all, I'm fairly new to working with operational amplifiers and so I'm just messing around with a few basic circuits. Had a comparator working fine to switch an LED on/off based on some variable reference voltage, but now I'm trying to get a working voltage follower. I have 2 different...
  6. Mayank_2606

    Can someone explain me the working of this circuit?? Squarewave Oscillator

    I am new to LTSPICE and have been experimenting with designing with op amps as filters and oscillators I recently came around this circuit of a "squarewave oscillator" in LMx58 Datasheet and with an aim to replicate it i decided to use an op amp in the LTSPICE viz. LT1007 to create a similar...
  7. S

    8th order sallen-key butterworth lowpass filter

    Hi guys, I'm running into some problems designing a 10MHz 8th order sallen-key butterworth lowpass filter. My requirements are: cornerfrequency f_c = 10 MHz max passband gain of 0.5dB filterorder of 8 available components: resistors, capacitors, op-amps What I have tried so far: I found...
  8. B

    Rail - to - rail opamp

    Hello, I've read something about a rail-to-rail opamp on the internet and I want to design one, just the soft part, and I am not sure if I get some things right. For example: Let's assume that my Supply Voltages are Vss = -5 V and Vdd=5 V In a rail-to-rail op amp I need my input to be anywhere...
  9. __Pai__

    What is the need for buffer or amplifier for ADC?

    This may be novice question. I am understanding SAR ADC specification for modeling perspective. In the mean time I was following analog devices Driving SAR ADC. In general what the necessity for a driver when it matches T acq and T cov of the selected ADC datasheet? What else test situation or...
  10. Angakok Thoth

    Shunt voltage reference in feedback of integrator/opamp?

    I have a common inverting integrators made using opamp (capacitor in negative feedback, +input to GND). I would like to have all these integrators saturate at the same exact voltage. Adding a zener diode in parallel to the cap works, but zeners are 2% tolerance at best and temperature dependent...
  11. D

    Buffer a high Voltage

    Hello, In my design I need to buffer about 45V-48V and about 30V. For this purpose I want to use two Opamps in Unity Gain Configuration and chose to use 2 ADA4522 (since it has an input range of 0-55V and low a low offset voltage, see attached schematic). In the simulation the buffer circuit...
  12. E

    purpose of using two opamp together

    Hi i am referring one opamp based design (designed by friend of mine)where two op amps are used. one in inverting configuration and other one is in non-inverting configuration. i am bit confused what would be the purpose of using two op amps together? here is attached schematic. (Here R4 is...
  13. D

    5V PWM to 12V analog for lighting control. Arduino

    Hey, so I've got to build the circuit to output the signal specified below I've currently got an Arduino UNO and I have written the code to output this. however, I can only put out 5v from my Arduino and the circuit requires 12V and 10V output, being able to switch between12 and 0v incredibly...
  14. S

    Phase and Gain of transimpedence amplifier and effect of input impedance

    Hello, I am new to hardware design. I am designing measurement circuit for Impedance Spectroscopy of electrochemistry cell. I need to measure the current coming from electrodes which have range from few milliamperes to few nanoamperes. as literature suggested, the equivalent circuit for...
  15. S

    4-20mA Analog sensor to 0-3.3V Digital conversion

    I have a question about signal conversion since I am pretty new to this. I want to translate a 4-20mA signal into a 0-3.3V digital signal. I have done a lot of research and came up with a circuit, but i am unsure if this is possible / correct. My idea was to use a Transimpedance amplifier to...
Top