Featured Post

High CMRR Instrumentation Amplifier (Schematic and Layout) design for biomedical applications

on
Instrumentation amplifiers are intended to be used whenever acquisition of a useful signal is difficult. IA’s must have extremely high input impedances because source impedances may be high and/or unbalanced. bias and offset currents are low and relatively stable so that the source impedance need not be constant. Balanced differential inputs are provided so that the signal source may be referenced to any reasonable level independent of the IA output load reference. Common mode rejection, a measure of input balance, is very high so that noise pickup and ground drops, characteristic of remote sensor applications, are minimized.Care is taken to provide high, well characterized stability of critical parameters under varying conditions, such as changing temperatures and supply voltages. Finally, all components that are critical to the performance of the IA are internal to the device. The precision of an IA is provided at the expense of flexibility. By committing to the one specific task of ...
2

IC Square wave Generator

on
This is a very simple square wave generator circuit built with IC 74LS00 that can accomplish aboveboard signals with frequencies amid 20 Hz and 1 MHz. Its adherence is acceptable abundant for a lot of applications. The achievement freq. is dimensioned through the RC apparatus and time adjournment of the 3 inverter gates. The time adjournment of a argumentation aboideau is the delayed time amid a change of ascribe accompaniment and the consistent change of the achievement state.



To prevent the temperature and voltage supply from affecting the frequency, the oscillator freq. fo must be smaller than 1/2tpn where:
tp = average delay time of each gate
n = the number of gates
The abova described oscillator has a tp of 10ns and n-3. The freq. is therefore:
fo << 1/2tpn = 1/2*10ns*3 = 16.6MHz
The voltage at the gate inputs varies from about _6V to -4V. The oscillation freq. can be made variable by using a 2.2KΩ potentiometer for R.

Comments

Post a Comment