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Oscillation Monitor – Circuit Schematic
Oscillation Monitor
The circuit in the diagram was originally designed to monitor an oscillator, but can also be used as a general-purpose level indicator for a. c. signals. It is ...
Isolated 1-Hz Clock – Circuit Schematic
Isolated 1-Hz Clock
One of the author`s physics projects required an accurate 1-Hz (seconds) clock signal. Unfortunately, precision 10-MHz quartz crystals are expensive, while anot...
Harmonic Generator With Single Opamp – Circuit Schematic
Harmonic Generator With Single Opamp
Quartz crystals have the property that their amplitude/phase characteristic repeats itself at frequencies that are an uneven multiple of the fundamental frequen...
Experimental Pendulum Clock – Circuit Schematic
Experimental Pendulum Clock
Using this design, you can construct an electromagnetically impulsed pendulum clock with a 1-second beat. On the prototype, the pendulum rod is 115cm long with ...
RC Differentiator – Circuit Schematic
RC Differentiator
A differentiating circuit is a circuit that produces pulses or that fades out input waveforms from its peak value all the way down to zero. To show this visuall...
Two Simple Crystal Test Circuits – Circuit Schematic
Two Simple Crystal Test Circuits
In the first circuit, above the BC548 is wired as a colpitts oscillator, the frequency tuned by insertion of a crystal. A good crystal will create high frequenc...
Low-Frequency Crystal Controlled Oscillator – Circuit Schematic
Low-Frequency Crystal Controlled Oscillator
The RF engineer sometimes has to look for an instrument that will check a low frequency quartz crystal unit reliably and rapidly. This is a difficult piece of e...
Designing 555 Astables – Circuit Schematic
Designing 555 Astables
If an oscillator of a particular frequency and mark to space ratio is required, (see Fig. 4. 4. 1) the method would be to calculate periodic time from the requi...
BJT Astable Multivibrators – Circuit Schematic
BJT Astable Multivibrators
The basic bipolar transistor (BJT) version of an astable multivibrator as shown in Fig. 4. 1. 1 has two outputs that repeatedly change state at a rate determine...
Wien Bridge Oscillators – Circuit Schematic
Wien Bridge Oscillators
A basic Wien Bridge Oscillator using a filament lamp with an op amp. It is a property of filament lamps that the resistance of the tungsten filament increases i...
Crystal Sine Wave Oscillators – Circuit Schematic
Crystal Sine Wave Oscillators
Where good frequency stability is required, in applications such radio transmitters, basic LC oscillators cannot guarantee to hold their frequency without some ...
Colpitts Oscillator Practical Project – Circuit Schematic
Colpitts Oscillator Practical Project
Build the Colpitts oscillator shown using either breadboard (proto board) or strip board, then test the oscillator`s operation using a multi meter and oscillosc...
The Colpitts Oscillator – Circuit Schematic
The Colpitts Oscillator
A typical Colpitts oscillator design. This circuit is very similar in operation to the Hartley oscillator described in Oscillators Module 2. 1 but the Colpitts ...
The Hartley Oscillator – Circuit Schematic
The Hartley Oscillator
The Hartley Oscillator is a particularly useful circuit for producing good quality sine wave signals in the RF range, (30kHz to 30MHz) although at the higher li...
Sine Wave Oscillator – Circuit Schematic
Sine Wave Oscillator
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Hartley Oscillator – Circuit Schematic
Hartley Oscillator
The HARTLEY OSCILLATOR is an improvement over the Armstrong oscillator. Although its frequency stability is not the best possible of all the oscillators, the Ha...
Crystals – Circuit Schematic
Crystals
Another frequency-determining device is the CRYSTAL. The crystal may be used with a tank circuit, or it may perform alone. Crystals exhibit a characteristic kno...
Beat Frequency Oscillator – Circuit Schematic
Beat Frequency Oscillator
The beat frequency oscillator (bfo) is necessary when you want to receive cw signals. Cw signals are not modulated with an audio component, you remember, so we ...
Armstrong Oscillator – Circuit Schematic
Armstrong Oscillator
The ARMSTRONG OSCILLATOR is used to produce a sine-wave output of constant amplitude and of fairly constant frequency within the rf range. It is generally used ...
Crystal Oscillators – Circuit Schematic
Crystal Oscillators
The circuit is only suitable for fundamental crystals as there are no mode suppression components. The oscillator transistor Q104 is cutoff most of the time exc...