Mini Operated Voice Relay Schematic
This mini-VOX voice operated relay is based on a circuit published in Silicon Chip, 9/1994, p31. The off delay time may be adjusted by varying R3 and R4. Reduci...
sound generator
The construction of this quite complicated circuit will be awarded with the joy of generating almost unlimited sound effects. The circuit can produce different ...
simple electronic organ
This electronic organ is very simple to construct and can provide hours of enjoyment particularly for children. The circuit is basically an emitter-coupled osci...
projector film changer
In synchronizing the audio and the projected film, a tone code must be used. This tone code triggers a device which automatically changes the film or slide. To ...
music in a chip
This 1-chip module can generate 9 different melodies. It is normally used as a doorbell, an acoustic signalling device or as a telephone "wait" melody. Once swi...
micprocessor
Audio processors are usually used in paging systems, in wireless intercom and the likes to amplify the microphone signal to a certain level. This can be done by...
Board layout and final schematic for Mosfet Compressor
Here is a link to the expresspcb layout for this compressor. If you are not familiar with expresspcb look it up. They provide a layout tool and it is very e...
Audio Visual Ringer
Audio Visual Ringer. Many a times one needs an extra telephone ringer in an ad-joining room to know if there is an incoming call. For example, if the telephone ...
Audio Light Modulator
Audio Light Modulator. Audio light modulations add to the enjoyment of music during functions organised at home or outdoors. Presented here is one such simple c...
Tone Control
Tone Control. Parts: Part Total Qty. Substitutions C1, C3, C5, C7, C15, C16 6 2.2uf Electrolytic Capacitor C2, C6 2 0.05uF Ceramic....
Simple Surround Sound Decoder
Simple Surround Sound Decoder. Introduction This surround-sound decoder is based on the Hafler principle, first discovered by David Hafler sometime in the early...
Simple High Quality Preamp For Hi-Fi
The new version has PCBs available, and is recommended for the best sound quality. If you need tone controls, you should see Project 97 which has excellent soun...
Expandable Graphic Equaliser
The project described in this article is a constant Q, fully expandable graphic equaliser. Where most conventional graphic EQ circuits have a Q that is depen...
Audio Graphic Equaliser
Audio Graphic Equaliser. Audio graphic equalizers are very common as commercial products (for Hi-fi, car audio and stage use) but circuits for them are very rar...
AUDIO AMP + 3KHz FILTER
AUDIO AMP + 3KHz FILTER. This circuit is the audio amp section for a complete optical transmitter. The increased circuit and filters the voice audio signals fro...
5 band graphic equalizer using a single IC/chip
5 band graphic equalizer using a single IC/chip. The BA3812L is a five-point graphic equalizer that has all the required functions integrated. ","0",...
10W Audio Amplifier with Bass-boost
10W Audio Amplifier with Bass-boost. High Quality, very simple design. No preamplifier required. Circuit diagram: Parts: P1 22K Log.Potentiometer (Dual-gang for...
3 Channel Audio Mixer
LM3900 [ PDF ] OP consist of four independent and internally compensated amplifiers in DIL14 package that are designed for wide single power supply voltage. ...
TV Muter Circuit
Many households are still graced by tube-type television sets. If you want to connect one of these large tellies to your stereo system to improve the sound qual...
Simple Mixer with 4 Input
A basic mixer suitable for mixing microphones or even effects outputs. The overall gain from input to output is one if the pot related towards the input is full...