The LM35 temperature sensor provides an output of 10 mV/C for every degree Celsius over 0C. At 20C the output voltage is 20 10 = 200 mV. The circuit consumes 00...
When SI (sensor) is closed, power is applied to U2, a dual timer. After a time determined by C2, CI is ene..
A high-gain amplifier using a UA741 is used to sense relative voltage drop in a conductor, and therefore current i..
A gas sensor (TGS823 from Allegro Electronics, Cornwall Bridge, CT 06754) conducts in the presence of explosive gases. U5 is a voltage-to- frequency converter that produces a frequency proportional to the sensor conductance. The output frequency ranges from 100 IIz in clean air to 8 kHz in a contaminated atmosphere. The dc voltage from the sensor also drives bar graph LED U7 and comparators U4-b and U4-c to sense present caution and danger levels. ..
The sensor is based on the selective absorption of hydrocarbons by an n-type metal-oxide surface. The heater in the device serves to burn off the hydrocarbons once smoke or gas is no longer present in the immediate area; hence, the device is reuseable. When initially turned on, a 15 minute warm-up period is required to reach equilibrium (V, = 0.6 V) in a hydrocarbon-free environment. When gas or smoke is introduced near the sensor, VA will quickly rise (rate and final.....
Using a capacitor sensor to detect a water level is a simple method of sensing. This circuit uses C5, which..
If a NiCad battery is discharged to a point at which the lowest capacity cell becomes fully discharged and reverses polarity, that cell will usually short internally and become unusable. To prevent this type of damage, this circuit detects a one-cell drop of 1.25 V and turns the load off before cell reversal can occur. Low-current zener or other voltage sensor Dl and resistors Rl and R2 establish a reference level for transistor Ql. ..
This is a cross-sectional diagram of a flex switch. They can be used as pushbutton or even position sensors. This schematic diagram shows an oscillator, which is used as an alarm sounder,..
Input current (from sensors connected to the patient) is limited to less than 5 µ under fault conditions. ..
The controller circuit can reduce a fan"s noise, power consumption, and wear, particularly in the presence of a low, fluctuating ambient temperature. Mount a temperature sensor in the fan"s airstream, and the circuit will adjust the fan speed as necessary to maintain a relatively constant sensor temperature. Input components Rl and Cl integrate the input square wave, producing a quasitriangular wave at the noninverting input of op amp IC1A. At this inverting input is a.....
In this proximity detector an NE567 tone decoder provides a signal of about 100 kHz that is fed to one sensor. The senso..
The sensor consists of two series-connected lN914s, part of the circuit of a 555 multivibrator. Wired as shown, the output pulse rate is proportional to the temperature of the diodes..
The sensing circuit rapidly disconnects the battery voltage and load whenever the voltage drops below a preset threshold. One-way operation prevents the circuit from reconnecting the load if the voltage should then rise above the threshold. Cl ensures that the circuit doesn"t activate while making connections to the battery; if you accidentally reverse these connections, Dl will block the turn on the relay. After you connect the battery, nothing happens until you.....
Two SCRs are used with two sensor loops. One loop uses series switches, the other loop parallel switches. When a switch actuation occurs, the SCR triggers...
Ql is used as an oscillator around 300 kHz. R9 is set so that the oscillator just begins to run. An object ne..
This circuit functions as a line-current sensor and can be connected in series with either of the phone lines. For the circuit to indicate an "in use" status for all phones on a single line, it must be connected in series with the phone line before, or ahead of all phones on the line...
This circuit provides interferenced rejection for the CW operator. The 567 phase-locked loop is configured to respond to tones from 500 to 1100 Hz. The Schmitt trigger reduces the weighting effect caused by the output of the PLL remaining low after removal of the audio signal. Ten to 15 millivolts of audio activate the circuit..
This circuit can detect smoke and a number of gases (CO, CO2, methane, coal gas and others) with a 10 ppm sensitivity. It uses a heated surface semiconductor sensor. Detection occurs when the gas concentration increase causes a decrease of the sensor element internal resistance..
Three-amplifier circuit consumes only 135 /tW of power from a ±1 V power supply. With a gain of 101, the instrumentation amplifier is ideal in sensor interface and biomedical preamplifier applications..
No electrical contact exists between the circuit and the conductor. The 7474 flip-flop is triggered by the output ..
Operational Amplifiers
Computer Systems
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Sensors & Detectors
ANSI Standards
Low Frequency Amplifiers
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