Advertisement
Steam locomotive whistle – Circuit Schematic
Steam locomotive whistle
The waveform of a steam whistle is a complex combination of white noise and an audio frequency oscillation. The noise generator is a transistor (Ql) biased into...
Train chuffer – Circuit Schematic
Train chuffer
The circuit consists of a white noise generator which only switches on with the high part of the square wave output from the clock circuit. The frequency of the...
Sound effects generator – Circuit Schematic
Sound effects generator
This circuit can generate a European police-car siren, bird noises, spaceship sounds, etc. In addition, it can be put to use as a doorbell, an alarm, etc. The c...
Simple color organ – Circuit Schematic
Simple color organ
Transformer Tl can be any matching transistor type in the range of 500/500 to 2500/2500 ohms. No connections from the SCR or its components are connected to gro...
Electronic ship siren – Circuit Schematic
Electronic ship siren
The circuit consists of a multivibrator (Ql & Q2), and a low power output stage Q3. The speaker should have an impedance in the region of 40 to 80 ohms. To use ...
One chip audio generator – Circuit Schematic
One chip audio generator
This high-quality low-cost generator covers 20 Hz to 20 kHz in three bands with less than 1% distortion. LM1-10 V, 14 mA (344,1869, 914) or 10 V, 10 mA (913, 36...
Audio notch filter 2 – Circuit Schematic
Audio notch filter 2
With the circuit shown here the response at one octave off tune is within 10% of the far out response: notch sharpness may be increased or reduced by reducing o...
audio notch filter – Circuit Schematic
audio notch filter
The circuit requires only one dual-ganged potentiometer to tune over a wide range; if necessary over the entire audio range in one sweep. The principle used is ...
Audio-powered noise clipper – Circuit Schematic
Audio-powered noise clipper
Tl and T2 are 600 to 8 ohm transformers (any transistor radio output transformers with 500 to 4 ohm impedance may be used). Ql is a 2N2222 npn transistor, and Q...
Noise limiter – Circuit Schematic
Noise limiter
This limiter improves signal-to-noise ratio. It is connected between the detector output and the audio input (if high impedance) or at some relatively high-impe...
Precise audio clipper – Circuit Schematic
Precise audio clipper
A differential amplifier makes an excellent audio clipper and can provide precise, symmetrical clipping. The circuit shown commences clipping at an input of 100...
Guitar and bass tuner – Circuit Schematic
Guitar and bass tuner
The heart of the circuit is IC2, a 50240 top-octave generator. That device uses a single input-frequency to generate all twelve notes of the musical scale. The ...
Metronome II – Circuit Schematic
Metronome II
This simple circuit uses a multivibrator to generate the beats and a subsequent audio amplifier stage to increase the output level....
Intercom – Circuit Schematic
Intercom
The circuit consists of separate amplifiers—one for each station—rather than a single amplifier and a time sharing arrangement. Ul and U2 are low-...
Balanced driver for line signals – Circuit Schematic
Balanced driver for line signals
This circuit will handle +24 dBm with ± 12 volts supply using TDA 1034s. ...
Bar-graph indicator for ac signals – Circuit Schematic
Bar-graph indicator for ac signals
Indicator was designed for displaying the peak level of small ac signals from a variety of transducers including microphones, strain gauges and photodiodes. The...
Background music decoder – Circuit Schematic
Background music decoder
A resistive voltage divider is used to establish a bias voltage for the input (Pins 2 and 3). The demodulated (multiplex) FM signal is fed to the input through ...
FDM stereo decoder – Circuit Schematic
FDM stereo decoder
For other input structures see Figures 6 to 11; shown here with PC-filter (Figure ß). The micropoco capacitor has a temperature coefficient of 125.10"6i 60....
TDM stereo decoder – Circuit Schematic
TDM stereo decoder
The circuit shown here with RC filter (Figure T). Micropoco capacitor has a temperature coefficient of 125 10"6 60.10" 6'C" V In simplified circuits a fixed re...
Stereo tv decoder – Circuit Schematic
Stereo tv decoder
The composite input signal is preamplified by transistor Ql and is then coupled to the high-pass filter composed of C3, C4, R6, and R7. The filtered audio is th...