Comparator Circuit | Electronic Project Circuits

Posts Tagged ‘Comparator circuit’

Comparator Based Crystal Oscillator

Although a simple crystal oscillator may be built from one comparator of an LT1720/LT1721, this will suffer from a number of inherent shortcomings and design problems. Although the LT1720/LT1721 will give the correct logic output when one input is outside the common mode range, additional delays may occur when it is so operated, opening the possibility of spurious operating modes. Therefore, the DC bias voltages at the inputs have to be set near the center of the LT1720/LT1721’s common mode range and a resistor is required to attenuate the feedback to the non-inverting input. Unfortunately, although the output duty cycle for this circuit is roughly 50%, it is affected by resistor tolerances and, to a lesser extent, by comparator offsets and timings.
If a 50% duty cycle is required, the circuit shown here creates a pair of complementary outputs with a forced 50% duty cycle. Crystals are narrow-band elements, so the feedback to the non-inverting input is a ?ltered analogue version of the square-wave output. The crystal’s path provides resonant positive feedback and stable oscillation occurs. Changing the non-inverting reference level can vary the duty cycle. The 2k-680? resistor pair sets a bias point at the comparator + (Comparator IC1a) and – (Comparator IC1b) input. At the complementary input of each comparator, the 2k-1.8k-0.1µF path sets up an appropriate DC average level based on the output. [...]

Be the first to comment - What do you think? Posted by admin - October 23, 2010 at 2:33 am

Categories: Op-amp circuit, Oscillator generator Tags: Comparator circuit, Oscillator generator, simple crystal oscillator

Compares with sound level tool

A tool that use for fine to decorate the sound of , organ , piano , have the pitch is equal. By have the accuracy is similar to with compare with the sound of the professional. But use the ability in listenning sound beat. At happen between 2 frequency sounds that confute by use origin frequency pillar circuit in 250.830 kHz frequency occurrences. For feed to reach first part of 5 IC. Which build the circuit divides by the frequency model a program.

Be the first to comment - What do you think? Posted by admin - August 7, 2009 at 7:29 am

Categories: Audio diagram, Meter Tags: Comparator circuit, Signal generator, sound level meter

Strength meter using IC741

This strength meter the test can by catch 2 metals. From that time squeeze meet. It will make LED stick bright arrange prevent according to one’s ability of squeezing the metal. The work of the circuit uses our body is formed lead the electricity changes to reach in the circuit. Which perform a temple resistance of the body. If we press wildly low resistance value make LED stick a lot of bright. By this circuit gives op-amp IC741 arrange each for other compare with voltage. In each the level of the intensity. We can stand the rapidity done to a turn VR1 and have LED Display 4 band. All in each band have IC741 detect voltage get and VR help fine the rapidity again the step. The detail is other , see in the circuit adds.