555 + LM386 PWM Speaker

A 555 timer generates a tone, the LM386 amps it up — your first audible analog circuit.

Difficulty: Through-hole. Estimated build time: about 60 minutes. Estimated parts cost: about US$6.00. 12-part bill of materials with live supplier pricing. A two-stage audio circuit that turns a 555 astable into something you can actually hear.