LM358 Wien-Bridge Sine Oscillator

An RC bridge plus an op-amp produces a clean 1 kHz sine wave — the only oscillator topology that gives you sines instead of squares.

Difficulty: Breadboard. Estimated build time: about 40 minutes. Estimated parts cost: about US$3.80. 8-part bill of materials with live supplier pricing. A Wien-bridge sine-wave oscillator built around the LM358 dual op-amp.