This self-heated constant-temperature-delta transistor anemometer is cheap, rugged, and sensitive. It relies on the relationship between airspeed and thermal impedance of a heated air flow sensor...
Linearized portable anemometer with thermostated Darlington pair
Measure humidity and temperature on one TTL line
By combining the responses of AD590 temperature sensor and a HS1101 humidity sensor, you can generate a single TTL-level signal containing information from both sensors...
Synchronous oscillator converts audio, video to FM
The synchronous oscillator and the coherent phase-locked synchronous oscillator are universal multifunctional networks that track, synchronize, and amplify as much as 80 dB; improve SNR by as much as 70 dB; and modulate AM, FM, and FSK signals...
Schottky diodes improve comparator's transient response
In a previous Design Idea, a circuit switches precision dc reference voltages to the noninverting input of a high-speed IC comparator. The circuit uses a 2-to-1 multiplexer that functions in a BBM fashion. Multiplexers have a parasitic capacitance...
Alarm monitors rotational speed of dc motor
You can use the circuit to monitor the rotating speed of a dc fan motor and sound an alarm if the motor stalls. One potential application of the circuit is monitoring the CPU-fan speed in a PC in which overheating the CPU can ruin the whole system...
Precision capacitive-sensor interface suits miniature instruments
In some applications of capacitive sensors, the instrument’s front end must be small enough to fit into a narrow space...
Wideband peak detector operates over wide input-frequency range
This Design Idea builds on a previous one to realize a precision peak detector with a bandwidth of 15 to 30 MHz or more, depending on the maximum input-signal level of your application...
FemtoAmp offers extreme gain range & isolation
Amplification of sub-picoamp signal currents is always a design challenge, especially when gain adjustment is required that spans multiple decades. A straightforward approach to the design task would normally involve potentiometers and teraohm feedback resistors...
Single op amp achieves double-hysteresis-transfer characteristic
In process-control applications requiring discontinuous controllers, the most elementary choice is a two-position-mode or on/off controller. A typical example of such a controller is a space heater...
Active Emulator Supports Multiple RTD Wiring, Sense Configurations
Before running a formal test with multiple resistance temperature detector (RTD) sensors, it is often necessary to calibrate and debug a data-acquisition system to verify basic functionality. The brute-force approach would be to wire all the sensors to the front-end board and use an environmental chamber to set the temperature of the RTDs...
