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  1. busevaran

    Need help on trying to control a motor speed with a PID circuit.

    Hi everyone! I'm Buse. I'm trying to control a motor speed for a personal project. You can find the schematic of the circuit I found on a book. This circuit works with only the PID parts constructed. My problem starts when I add the other parts. For example, U1 opamp (top left) is supposed to...
  2. Alex_bam

    Problem in demodulating differententially modulated signal.

    Hello everyone, I am designing LPF based differential demodulator(LPF_DDM) to retrieve differentially modulated signals, which are on-chip capacitive isolated [shown]. LPF_DDM includes a differential amplifier, LPF, and Schmitt trigger. I designed a two-stage opamp [specification below], as a...
  3. L

    Problem seeing the hysteresis curve of the inductor in the ltspice.

    Hello I'm trying to implement the function Flux = 55m * tanh (5 * x), but I'm just getting errors. Does anyone know any way to solve this?
  4. D

    Can't get the OpAmp working

    Hi Guys I am working on a private project where I need to detect a blue light flashing up. But the OpAmp I am using is always on HIGH regardless of the brightness of the blue light. I have also tried various OpAmp circuits but they all resulted in the same. I've tried feedback resistors of up...
  5. P

    LTSPICE opamp circuit sim

    I'm trying to sim the input circuit of an audio EQ, but I'm getting only DC at the output. This is what I'm trying to simulate: It's the input section of this schematic: Here's what I've created, the .ASC is attached: I'm using an LT1057 model as it is described as a drop-in...
  6. L

    Replacement for NJM5532 (Australia)

    Hello I am currently build GreatScott's diy microphone and he uses an NJM5532 op amp but those are not readily available here in Australia. I have looked into buying them online however, shipping cost around $20 and that's very expensive compared to the price of the op amp. Does anyone know a...
  7. hesam_m

    Amplification of the signal decay

    I should amplify a low impedance signal with the peak of maximum 1.4V. The tricky part is that the signal itself is not important but the tail of the signal is important which might show some decay (falling edge could reach to zero sooner or later than normal) and these signal decay variations...
  8. M

    One speaker is picking up radio module noise

    I currently made a module to my project which isn't quite functioning correctly. It's 4 distinct parts on one board. The radio I/O, the two independent sound amplifiers out of the LM386's and the RFID card reader. This is the circuit: The actual inverter IC I used is 74HCT04 because it...

    For a better sine wave

    Hello sir, This post might be a silly one, but my stupid brain does not find it well. I am looking for a signal generator circuit to fed different frequencies in other circuit. I have found one, take a look But, the person who posted this did wrong on inverting and non inverting sign...
  10. S

    Piezoelectric Transducer with Arduino

    I want to drive piezoelectric transducer with resonant frequency 110khz and input voltage 70 volts ac with arduino. I generated a square wave of same frequency with arduino than converted it into ac voltage using RC filter than for the step up I used transformer small getting amplitude of 67...
  11. R

    Amplify current to UV-LED

    I have a function generator (Escort EFG 2210) as a source to a UV-LED (LED255J ). The FG delivers about 7.5 Vrms and 30 mA pulse signal. The LED requires closer to 100 mA for optimal emission. The voltage is good enough. I have tried various amplifier circuits, but end up with less current than...

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