These are Tone control circuit using op amp - NE5532 or 4558 IC as low noise, with PCB layout, can adjust sound frequency and tone bass, treble, mid and..
This is a simple temperature to voltage converter circuit or an Electronic thermometer circuit there. Which will operate in a temperature range of 0 to 24 degrees Celsius (32 to…
To change the voltage to current
Wien bridge oscillator is sine wave oscillator. It can generate a big of frequencies. The oscillator has based on a bridge circuit, which compose four resistors and two capacitors.