Tag «Sound Sensor»

Sound-Controlled Relay

This is a relay circuit that detect the presence of sound to activate the relay. You can use this sound-controlled relay as voice operated switch, light control, toys, or any other application that can be controlled by a switch. Just replace the switch with  this relay and now you have a sound-controlled device. This circuit …

LM10 Single-Cell Microphone Amplifier

This is a Single-cell microphone amplifier circuit. This circuit produce a voltage gain of 60 dB at 500Ω load with bandwidth 5kHz. This circuit can provide a 60dB gain up to 10kHz if it is unloaded. This circuit has a 10 kΩ input impedance. This circuit cannot neither produce an output swing closer than 800mV …

Microphone Pre-Amplifier with Tone Control

Microphone can’t be directly connected to a power amplifier because the signal is too weak. Standard audio power amplifier accept about 1 Vrms to give a full volume (maximum power), and off course there’s such microphone has such high level output. To provide signal with high enough amplitude, we can use a pre-amplifier circuit shown …

Door Intercom

Door intercom is very useful for home security. If you receive a door knock or door bell/alarm, you can push this intercom knob and ask the guest  to identify his/her self, before deciding to open the door to welcome. Here is the schematic diagram of the circuit: To install this door intercom, except for right …

Low Noise Microphone Pre-Amp with Op-Amp

Microphone pre-amp is a very simple circuit, most all low noise op-amp will be sufficient for this circuit (TL071, TL082, OPA371, NE5534, etc). This circuit will be suitable for dynamic microphone, electret microphone (or a condenser microphone with active circuit inside). A condenser microphone (without voltage bias source) won’t work for this circuit. If you …