electronic circuit

  1. D

    Simulating a RF transmitter bug in LTspice

    hey guys i,m new to this forum and Lt spice I am planning on building a FM bug using hardware, i am trying to simulate this circuit using LTspice In simulation i am replacing the microphone with a voltage source of 10mV and 2kHz then removing 68k resistor. simulation file is attched.Kindly...
  2. Guru_007

    How to design H-bridge motor driver circuit using BJT transistors?

    Hi, I don't know exactly on designing H-bridge motor driver using BJT. I have no idea in selecting BJT's for required specification and selecting current limiting resistor values. Is it required to use zener diode as a protection to the circuit? Kindly guide me. Thanks & regards Guru
  3. J

    Not able to operate buck-boost converter.

    Greetings, I am facing issue with TPS61240 as a buck-boost converter. I am using TP4056 to charge the battery and DW01 (and FS8205) to protect the battery by referring this blog. Also, note that I want to operate the other module; due to this I am using this below shown circuit to high/low...
  4. Andreas.K

    Problem with linear power supply.

    Hello guys , i am a novice engineer and i have an old linear power supply for a video door phone system. The P.S. has a 12VAC output (good) , a +15VDC output (bad) and a +18VDC (good). DC outputs share same GND. The problem is when there is no load on GND and +15VDC output i measure a voltage...
  5. mdafifmumtahin

    Help about electronic circuit (DAC with op amp)

    Can anyone please solve this problems ?
  6. S

    Analysis generate PWM use op-amp.

    Please help me to understand this circuit about analysis voltage each point and how to calculate time charge and discharge time on triangle signal. If use Op-Amp NJM2904C Thank you.
  7. abdaelawad

    Calculate the voltage V4 and current i6 of the circuit in the figure using only Kirchhoff and law of nodes and meshes

    I tried to solve the equations I got but when I make substitutions I get to a deadlock where I can't substitute anything anymore. The equations I obtained are: i2=i1+i2 i3=i4+i5 i5=i7-i6 i2=i4+i6 3i2-i1R1-i5R2=0 2v-i2R3=0 -i6R4+2v-i5R2=0 Could someone help me understand step by step what...
  8. B

    Creating own Electromagnets & Calculating the Forces between them

    So basically I’m trying to create my own electromagnets and conduct my own experiments. I’ll have an arduino microcontroller send a current into the wire that is coiled around the magnet, thus increasing the strength of the magnetic field, which in turn will touch with other magnets. I want to...
  9. Elgordoroberto

    Ic led switch circuit

    Hello all, I’m helping my daughter with a design project and part of it needs a simple led control circuit. Using a single push button and 4 leds, I need an ic circuit that would light led 1 with th e first button push, led 1 &2 with the second, led 1,2,&3 with the third button push, leds...
  10. Sheilarohr

    Complex circuit

    We are suppose to make a complex ckt with a 9v battry, a buzer and 2 lights. MY battery keeps heating up. Should i try a lower volate bulb?
  11. D

    AC- Reverse Voltage and current flowback system.

    Hi, I'm Nayan and I am working on a project to control the reverse flow of current and voltage of an AC power source from a small inverter circuit. This would be helpful to connect an On-Grid solar inverter to stop the feed-in mechanism to the reference power source to run the inverter in power...
  12. E

    Turn on the Common Cathode Seven Segment using PNP transistor

    I am using seven segment in my project and i was using common cathode and using npn transistor i was able to switch by making arduino pin HIGH. But now i want to display the data on seven segment when i make the pin as LOW. I mean i want to select the Segment when i will make it LOW. i was...
  13. ecaits

    Op amp used in cyclic voltammetry application

    In cyclic voltammetry application (as per circuit design given in image), the voltage difference between reference electrode (RE) and working electrode (WE) will be constant. As per REDOX process (Reduction & Oxidation), the current will flow between counter and working electrode. The circuit...
  14. R

    Tesla Coil Not Working. Transistor Getting Extremely Hot

    Tesla Coil Not Working. Transistor Getting Extremely Hot. See The image Below. I Did not use a switch and i did not use an led
  15. E

    Controller gets hang on Relay switching

    I am using a relay to turn ON/OFF the AC load. But when i turn ON and turn OFF the AC load (230 VAC) 3-4 times my controller gets hang. Here is my circuit diagram for the relay. The ground is common in all over schematic. What changes do I need to do for improving the noise?
  16. E

    DC current sense using Opamp

    I want to measure a current consumption for DC fan. I am using OPA2197 opamp for the same. Following is the circuit diagram. i want to understand if this circuit missing anything?
  17. Answerz

    PsOC 4 BLE (pins problems)

    I am running a project using a thermistor. I started by using the evaluation board as shown: The program runs fine. After that, I removed the module from the evaluation board and powered the module using an external power source (3V). I moved the resistor and thermistor from the evaluation...
  18. A

    detect pressure of the arm coming together

    hi I am developing simple circuit where I am trying to detect pressure when arms coming together when hand bended. the device will be placed near the L bow of hand and when user bend the arm, the device measure the pressure and beep if pressure is higher than set limit. I know micro controller...
  19. Lambo Av

    Doubts on How Connector Works

    Hi all, I am currently reviewing this Degson DG2002-4.0 connector. https://www.degson.com/content/details_123_10715.html May I know what does the arrow above the connector mean? And what do the holes beside the arrow does? Based on the photo below, there is this operating tool which can be...
  20. D

    Non-Inverting Amplifier (AC Coupled) : How to solve this circuit with lower and high frequency?

    I need to design this circuit with a gain of 26 for signals where the frequency varies from 800Hz to 8kHz and I also need to find out the current on the RL load. (VA = 100mV) Will C1 behave like an open circuit in ac analysis? I am getting to lower the frequency (800Hz) but I am not able to...
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