A flashing light of high brightness and short duty cycle is often desired to provide maximum visibility and battery life. This necessitates using an output transistor, which can supply the cold filament surge current of the lamp while maintaining a low saturation voltage. ..
This field strength meter consists of a tuned crystal detector producing a dc output voltage from a transmitted signal. The dc voltage is used to shift the frequency of a transmitter of 100-mW power operating at 1650 kHz. The frequency shift is proportional to the received field strength...
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...
This circuit has a 100-m V hysteresis which can be used in applications where very fast transition times are required at the output, even though the signal input is very slow. ..
In this circuit, audio fed to the control channel is amplified and rectified by Dl and D2. This dc level activates LED D3 via Q2. The light from D3 causes R9, a light-dependent resistor to decrease resistance. As Rll (audio gain) is set higher, more audio is present at the output of Ql. Audio fed into J2 is shunted to ground via R9 and less of this audio appears at J3...
The circuit consists of two basic circuits, the oscillator and the detector. The oscillator uses an FET in a Colpitts configuration. The energy circulating in the oscillator tank is coupled through C4 to the detector circuit, where a small diode (D2) rectifies it, feeding a dc voltage to the Darlington pair (Q2, A3) controlled by the sensitivity control (R3). Any small variations in the bias of the amplifier will cause large variations of current through the LED indicator.....
Assume the correct phase sequence to be VA-VB-VC. The circuit terminals are connected such that Tl gets connected to phase A and T2 to phase B. The capacitor advances the voltage developed across R2 due to phase "B" by — 60°, while the voltages developed across it by phase "A" is in phase with VA as shown in Fig. 69-1. The net voltage developed across R2 ~ zero, the neon lamp is not energized, thereby signaling correct phase sequence. If terminal T2 gets.....
A positive going input charges C through the IN4148 and R. The diode keeps the scs off. ..
Using an ionization chamber and a high-impedance (CA3130) op amp, the presence of smoke will cause the CA3130 ..
Using an intersil ICL 7106 A/D converter chip and an LED display module, this gauge uses a Sensym Corp. pressure tra..
An NE602 acts as a heterodyne detector and Ql as a sense oscillator. When Ll is brought near metal, it causes a charge in lo..
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. ..
This is a 8048/IM80C48 Microcomputer with 8 character 16-segment ASCII triplex liquid crystal display. The two bit character address is merged with the data and written to the display driver under the control of the WR line. ..
This circuit uses the CA3207 sequence driver and CA3208 segment latch-driver in combination to drive display devices of up to 14 segments with up to 14 characters of display. ..
This self-biasing configuration is useful any time srnall changes in light level must be detected, for example, when monitoring very low flow rates by counting drops of fluid. In this bias method, the photodarlington is de bias stabilized by feedback from the collector, compensating for different photodarlington gains and LED outputs. The 10-I"F capacitor integrates the collector voltage feedback, and the 10-MO resistor provides a high base-source impedance to minimize.....
The use of a switching transistor (like a 2N2222 or 2N3904) allows use of the CD4511B with a common-anode display. should be chosen to provide about 1 mA to drive Ql and Rr should provide enough current to drive the display...
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.....
This receiver consists of an input network amplifier IC7 FSK PLL detector ICG, and output am..
With the 555 timer connected as a multivibrator and an opto-isolator, ..
This window comparator generates an output pulse for each event that occurs within a specified window. That is, each output pulse signifies an input voltage pulse or level change that exceeds VREFLOW. but not VREFHIGH· The monostable multivibrators, IC2A and IC2B, produce a 10-l"s pulse at their Q output in response to a rising edge at their A input. Comparator IC1B produces a rising edge when the input exceeds VREF Low and comparator IC2A produces a rising edge.....
Operational Amplifiers
Computer Systems
Oscilloscopes
Transmitters & Receivers
Sensors & Detectors
ANSI Standards
Low Frequency Amplifiers
Power Amplifiers
Number Systems
Regulated Power Supplies
Analogue Filters
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