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Posts Tagged ‘TL071’

Band rejection filter using TL071

The band rejection filter circuit is not wide filter that can denial the frequency up to 60dB by we used the TL071 single chip op-amp it is very low distortion and work good at output to maximum to 100kHz or the range 1Hz to 20kHz
In the circuit we defined three resistors R1,R2,R3 are like value to 100K, and then two capacitors C1,C2 are equal to 330pF, For will reject the frequency at 50Hz.
By we can select the parts with the formula is F = 2×3.14xRC , And to get rejection well than 40dB if we should the resistor matched to 0.1% and capacitor to 1%.
The circuit is the right narrow filter for well audio system, we hope you enjoy with this circuit ideas.

Be the first to comment - What do you think? Posted by admin - May 15, 2012 at 12:47 pm

Categories: Audio diagram, Op-amp circuit, Oscillator generator Tags: Band rejection filter, Filter circuits using op amp, TL071

Super Light Sensor

This “Super Light Sensor” responds to minute fluctuations in light level, auto-adjusting over the range from about 200 lux up to 60,000 lux (ie, from a modestly lit room to direct sunlight). It has lots of potential uses – eg, detecting a car entering a driveway, a person moving in a room, or wind rustling the leaves of a tree. At the same time, it has a high level of rejection of natural light variations, such as sunrise, sunset and the movement of clouds. While it is a “passive” system, it can also be used as an “active” system – ie, used in conjunction with a light beam.

Its great advantage here is that, since it responds to fluctuations in light level rather than the crossing of a specific light threshold, it is much more flexible than other typical “active” systems. It can be placed within the line-of-sight of almost any light source, including “vague” ambient light, and simply switched on. As shown, the LDR is wired as part of a voltage divider so that, between darkness and full sunlight, its output at “X” varies between about one-quarter and three-quarters of the supply voltage. A wide variety of sensors may be used in place of the LDR, including photo-transistors, photo-diodes and infrared and ultraviolet devices.
he signal from the sensor is fed to the inputs of comparator IC1 via two 150kO resistors. However, any signal fluctuations will be slightly delayed on pin 3 compared to pin 2, due to the 220nF capacitor. As a result, the pin 6 output of the comparator (IC1) switches low during short-term signal fluctuations and this triggers monostable timer IC2. IC2 in turn switches on transistor Q2 which activates Relay 1. It also lights LED1 via a 1.5kO current-limiting resistor. Trimpot VR2 allows the monostable period to be adjusted between about 3s and 30s.

As with all such circuits, the Super Light Sensor may not work as well under AC lighting as under natural lighting. If AC lighting does prove a problem, a 16µF (16V) electrolytic capacitor can be connected between the sensor output and ground to filter the signal to the comparator. When pin 3 of IC2 goes high, FET Q1 also turns on and pulls pin 2 of IC2 high. This transistor remains on for a very short period after pin 3 goes low again due to the 100nF capacitor on its gate. This “blanking” is done to allow the circuit time to settle again after the relay disengages (and stops drawing current).
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Author: Thomas Scarborough – Copyright: Silicon Chip Electronics Magazine
Link: http://www.extremecircuits.net/

Be the first to comment - What do you think? Posted by admin - August 30, 2010 at 10:57 pm

Categories: Detector, Lighting Tags: LDR sensor, lighting sensor, sunlight sensor switch, TL071

6 Input Mixer by IC 741 , LF351 ,TL071

Description:
A simple mixer with 3 line inputs and 3 mic inputs using commonly available parts.

Notes:
The mixer circuit below has 3 line inputs and 3 mic inputs. The mic inputs are suitable for low impedance 200-1000R dynamic microphones. An ECM or condenser mic can also be used, but must have bias applied via a series resistor. As with any mixer circuit, a slight loss is always introduced. The final summing amplifier has a gain of 2 or 6dB to overcome this. The Input line level should be around 200mV RMS. The mic inputs are amplified about 100 times or by 40dB, the total gain with the mixer is 46dB. The mic input is designed for microphones with outputs of about 2mV RMS at 1 meter. Most microphones meet this standard.

The choice of op-amp is not critical in this circuit. Bipolar, FET input or MOS type op-amps can therefore be used; i.e 741, LF351, TL061, TL071, CA3140 etc.

Source :: http://www.zen22142.zen.co.uk/Circuits/Audio/6ipmix.htm