Magdi Mohamed Mashly

In this paper a new realization of the differential input balanced output current opamp is proposed, operating with ±1.5 V supplies. Its architecture is based on the use of current inverters to sense the input currents while providing a very low input resistance, 23 $Ømega$. The opamp provides a maximum output swing of 700 $μ$A, with an input offset current of 3.5 nA. The differential gain achieved is 65.5 dB, and the differential structure adopted in the design provided a high CMRR, 89.5 dB, the proposed circuit is compared to other realizations with single and differential inputs. The applications of the current opamp are exploited some new applications are presented such as: MOSFET-C integrators, full non-linearity cancellation for MOS transistors, and finally a digitally tuned current-mode variable gain amplifier, which has a gain tuning range of 25 dB with a 0.05 dB step.

The optical obsorption, real (ε′) and imaginary parts (ε″) of the dielectric constant, dc conductivity (σ), and I-V characteristics of polyvinyl alcohol (PVA)-gelatin blend were investigated in the temperature range of 290 to 460 K. The identification of the structure and assignments of energy bands were derived in terms of the ligand field theory. The main absorption band at 244 nm, was affected by the gelatin concentration. Two relaxation processes namely αa and αc were obtained at the glass-rubber transition temperature Tg. The first one is due to the rotation of free C=O and NH2 groups inside the amorphous part of PVA while the second one is due to the rotation of the conjugate of C=O groups and semi-crystalline structure on PVA. The calculated values of the activation energies provide us the information about the presence of ionic conduction. At 303 K the conduction mechanism is Ohmic because there is no injection carriers from the electrode contact, while Richardson-Schottky (RS) effect is predominant in the second region at T ≥ 333 K. © 2005 IACS.

The optical obsorption, real (ε′) and imaginary parts (ε″) of the dielectric constant, dc conductivity (σ), and I-V characteristics of polyvinyl alcohol (PVA)-gelatin blend were investigated in the temperature range of 290 to 460 K. The identification of the structure and assignments of energy bands were derived in terms of the ligand field theory. The main absorption band at 244 nm, was affected by the gelatin concentration. Two relaxation processes namely αa and αc were obtained at the glass-rubber transition temperature Tg. The first one is due to the rotation of free C=O and NH2 groups inside the amorphous part of PVA while the second one is due to the rotation of the conjugate of C=O groups and semi-crystalline structure on PVA. The calculated values of the activation energies provide us the information about the presence of ionic conduction. At 303 K the conduction mechanism is Ohmic because there is no injection carriers from the electrode contact, while Richardson-Schottky (RS) effect is predominant in the second region at T ≥ 333 K. © 2005 IACS.

The optical obsorption, real (ε′) and imaginary parts (ε″) of the dielectric constant, dc conductivity (σ), and I-V characteristics of polyvinyl alcohol (PVA)-gelatin blend were investigated in the temperature range of 290 to 460 K. The identification of the structure and assignments of energy bands were derived in terms of the ligand field theory. The main absorption band at 244 nm, was affected by the gelatin concentration. Two relaxation processes namely αa and αc were obtained at the glass-rubber transition temperature Tg. The first one is due to the rotation of free C=O and NH2 groups inside the amorphous part of PVA while the second one is due to the rotation of the conjugate of C=O groups and semi-crystalline structure on PVA. The calculated values of the activation energies provide us the information about the presence of ionic conduction. At 303 K the conduction mechanism is Ohmic because there is no injection carriers from the electrode contact, while Richardson-Schottky (RS) effect is predominant in the second region at T ≥ 333 K. © 2005 IACS.