AMPLIFIER CIRCUITS

Basic Op-Amp-based Non-inverting Amplifier

Microphone Pre-Amplifier

LM380-Based Audio Amp Circuits

Simple Audio Amplifier

Non-Inverting AC Amplifier

Inverting AC Amplifier

MIXER CIRCUITS

Simple Audio Mixer

FILTER CIRCUITS

Op Amp-based Low Pass Filter

Op Amp-based High Pass Filter

Butterworth Low Pass Filters

Butterworth High Pass Filters

Tunable Band Pass Filter

Wien Bridge Notch Filter

Twin-T Notch Filter

Peaking Amplifier Filter

OTHER AUDIO/RF CIRCUITS

Op Amp-based Sound Detector

Simple Frequency Meter

Sound-to-'Dancing Lights' Converter

See also: Tone Generator circuits...