This simple circuit generates a good 1KHz sine wave adopting the inverted Wain bridge configuration (C1-R3 & C2-R4). It features a variable output, low distortion and low output impedance in order to obtain good overload capability. A small filament bulb ensures a stable long term output amplitude waveform. 1KHz Sine wave Generator Circuits Diagram Notes: The bulb must be a low current type (12V 40-50mA or 6V 50mA) in order to obtain good long term stability and low distortion. Distortion @ 1V RMS output is 0.15% using a 12V 40mA bulb, raising to 0.5% with a 12V 100mA one. Using a bulb differing from specifications may require a change of R6 value to 220 or 150 Ohms to ensure proper circuit's oscillation. Set R5 to read 1V RMS on an Audio Millivoltmeter connected to the output with R7 rotated fully clockwise, or to view a sinewave of 2.828V Peak-to-Peak amplitude on the oscilloscope. With C1, C2 = 100nF the frequency generated is 100Hz and with C1, C2 = 1nF frequency ...