Free electronic circuit design and schematic diagram
The UJT below is configured to produce a sawtooth wave at a frequency of 104 Hz. The capacitor begins to charge through the 4.7 kOhm resistor when the circuit is initially powered up. The current suddenly flows from the UJT emitter (E) to the UJT Base (B1) when the voltage across the capacitor rises to a certain point. This will […]
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The Vc1 increases linearly when the pull-up resistor RA in the monostable circuit is replaced with constant current source, generating a linear ramp. The linear ramp generating circuit and the generated linear ramp waveforms illustration is shown in figures below. Current source is created by PNP transistor Q1 and resistor R1, R2, and Re. Ic= (Vcc-Ve)/Re Ve= Vbe + (R2/(R1+R2))Vcc […]
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The purpose of developing this circuit is to allow watch crystals to be used in an existing CMOS oscillator circuit that was to run from a 12 V supply. But there is a problem, these crystal only work uo to a supply voltage of about 6V. If the supply voltage is more than 6 V then the crystal will be […]
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The circuit diagram below shows a constant amplitude triangular-wave generator. A variable frequency triangular wave whose amplitude is independent of frequency is provided by this circuit. As a reset circuit, the generator embodies an integrator as a ramp generator and a threshold detector with hysteresis. There is no further explanation is needed because the integrator has been described in a […]
Read moreThis is Operational an Amplifier (Op-Amp) Oscillator circuit. This circuit has some advantages, they are this circuit can be operated at low frequencies with relatively small capacitors, it has a completely-symmetrical output waveform along with a buffered output and it will always self start and cannot hang up because there is less dc positive feedback than negative feedback. Returning R2 […]
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This is a Colpitts-crystal oscillator circuit. It is suitable for low frequency crystal oscillator circuits. Using the 2N3823 JFET, this circuit has excellent stability because the temperature will not vary the 2N3823 JFET circuit loading. Here is the circuit : [Source: National Semiconductor Application Note]
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With very low harmonic distortion, 2N4416 JFET is suitable to smoothly oscillate in a circuit. On application where low harmonic content is required for a good mixer circuit, JFET local oscillator is very good. Below is the circuit diagram of Low Distortion Oscillator: And here’s the 20 MHz Oscillator Values C1 = 700 pF L1 = 1.3 mH C2 = […]
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