The opportunity of making a frequency-tunable perform generator with rectangular and triangular pulses of fixed amplitude and digital synchronous management of equal capacitances within the grasp generator and integrator is proven. Such management is feasible as a consequence of using voltage repeaters within the suggestions circuit the place capacitors are included by means of the transmission coefficient regulator.
Wow the engineering world together with your distinctive design: Design Concepts Submission Information
Nicely-known practical mills include a grasp generator of rectangular pulses the place an integrator primarily based on an RC-circuit is linked on the output, by which a resistor performs the function of a steady present generator. This offers a linear cost and discharge of the capacitor with the formation of a triangular-shaped voltage on its plates.
The drawback of the classical scheme is that such a generator is able to working at just one frequency, since when it adjustments, the amplitude of the triangular output sign adjustments noticeably. To make sure the potential of altering the frequency of such a generator whereas sustaining a steady amplitude of the triangular output sign, it’s essential to make use of an amplitude stabilization scheme, or alter the capacitance of the integrator capacitor synchronously with the change within the era frequency.
It’s attainable to resolve the issue of synchronous frequency change of the grasp generator and the corresponding proportional change within the capacitance of the integrator capacitor by utilizing digital regulation of the equal capacitance of its capacitors. The precept of digital management of the parameters of RLC-elements is described in [1–7]. Such management of the equal parameters of the energetic and reactive components is feasible, for instance, by means of using voltage repeaters within the suggestions circuit of which these components are included by means of the transmission coefficient regulator [7].
If a potentiometer is linked to the output of the voltage repeater, Determine 1, and a capacitor C0 is linked between its sliding contact and the enter of the repeater, then the equal capacitance of the capacitor Cequ will change from nominal to nearly zero when adjusting the potentiometer in keeping with the formulation Cequ = C0(1 – Ktrans), the place Ktrans is the switch coefficient from the enter of the voltage repeater to the sliding contact to the potentiometer, Ktrans = 0…1.
Determine 1 Electrical scheme of a practical generator with digital regulation of the equal capacitance of its capacitors.
The perform generator in Determine 1 incorporates the RC-generator of rectangular pulses on the operational amplifier U1.1 of the LM348 chip. Indicators from the generator output with a frequency of 100–1000 Hz and are fed to the integrating chain R3, C2, by which the high-resistance resistor R3 acts as a steady present generator. A triangular-shaped sign is fashioned on the plates of the capacitor C2. Additional, from the output of the voltage repeater on the operational amplifier 1.3, the sign by means of the separation capacitor C3 enters the amplification stage on the operational amplifier U1.4.
The equal capacitance of capacitors C1 and C2 decreases when the suggestions voltage is utilized to certainly one of its plates. This voltage coincides in section with the enter voltage and is regulated by a twin potentiometer R6.1 and R6.2.
Michael A. Shustov is a health care provider of technical sciences, candidate of chemical sciences and the writer of over 750 printed works within the subject of electronics, chemistry, physics, geology, drugs, and historical past.
Associated Content material
- Synthesize variable in-circuit Rs, Ls, and Cs
- Electronically-variable capacitor with big selection and excessive worth
- Inductance comparator
- Rectangle and triangle waveform perform generator
References
- Miller J.M. “Dependence of the enter impedance of a three-electrode vacuum tube upon the load within the plate circuit”. Scientific Papers of the Bureau of Requirements, 1920, Vol. 15, No. 351, P. 367–385.
- Sheingold D.H. “Impedance and admittance transformations utilizing operational amplifiers”. The Lightning Empiricist, 1964, Vol. 12, No. 1, P. 1,2,7,8.
- Gaon J. “Suggestions turns fastened capacitor into variable capability”. Electronics, 1966, Vol. 39, No. 24 (Nov. 28). P. 80.
- Korshunov A.I. “Easy regulation of capacitance of capacitors”. Energy Electronics (RU), 2014, No. 4 (49), pp. 36–40.
- Plasoianu Gh. “Electronically-variable capacitor with big selection and excessive worth”. EDN. June 20, 2018. https://www.edn.com/electronically-variable-capacitor-with-wide-range-and-high-value
- Shustov M.A. “Vernier steady present generator of drip kind for the vary 10–6…10–11 A”. Radiolotsman (RU), 2018, No. 9, pp. 42–44. https://www.rlocman.ru/shem/schematics.html?di=538827
- Woodward S.W. “Synthesize variable in-circuit Rs, Ls, and Cs”. EDN, February 19, 2019. https://www.edn.com/synthesize-variable-in-circuit-rs-ls-and-cs/
- Shustov M.A. “Digital regulators of parameters of RLC-elements”. Radiolotsman (RU), 2023, No. 3–4. https://www.rlocman.ru/overview/article.html?di=658565
googletag.cmd.push(perform() { googletag.show(‘div-gpt-ad-native’); });
–>
The publish Operate generator with digital regulation of capacitors appeared first on EDN.