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Water-level-sensor-and-control – Circuit Schematic
Water-level-sensor-and-control
When the water level is low, the probe is out of the water and SCRl is triggered on. It conducts and imposes a heavy load on transformer Tl"s secondary winding...
Fluid-level-control – Circuit Schematic
Fluid-level-control
This circuit is designed to detect the presence or absence of aqueous fluids. An ac signal generated on-chip is passed through two probes within the fluid. A d...
Low-flow-rate-thermal-flowmeter – Circuit Schematic
Low-flow-rate-thermal-flowmeter
This design measures the differential temperature between two sensors. Sensor Tl, located before the heater resistor, assumes the fluid"s temperature before it...
Direction-detector-decoder – Circuit Schematic
Direction-detector-decoder
This circuit, which was developed to monitor the traffic of bumblebees in and out of the hive, differentiates a-to-b motion from b-to-b motion. When used with ...
Signal-conditioner-with-bridge – Circuit Schematic
Signal-conditioner-with-bridge
The LT1007 is capable of providing excitation current directly to bias the 350-0 bridge at 5 V. With only 5 V across the bridge, as opposed to the usuallO V, t...
Bridge-transducer-amplifier – Circuit Schematic
Bridge-transducer-amplifier
In applications involving strain gauges, accelerometers, and thermal sensors, a bridge transducer is often used. Frequently, the sensor elements are high resis...
Remote-sensor-loop-transmitter – Circuit Schematic
Remote-sensor-loop-transmitter
This circuit shows amplifier Al as a sensor amplifier in a bridge configuration. Amplifiers A2 and A3 are configured as a voltage to frequency converter and A4...
Ultrasonic switch – Circuit Schematic
Ultrasonic switch
Receiver. Output from the transducer is amplified by Ql and Q2, and rectified by Dl. Voltage on pin 2 of ICl will go more negative as the input signal increases...
Temperature-to-frequency converter – Circuit Schematic
Temperature-to-frequency converter
The circuit exploits the fact that when fed from a constant current source, the forward voltage of a silicon diode varies with temperature in a reasonably linea...
Digital thermometer – Circuit Schematic
Digital thermometer
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 tem...
Temperature meter – Circuit Schematic
Temperature meter
TCA965 window discriminator IC allows the potentiometers RVl and RV2 to set up a window height and window width respectively. Rl and thermistor THl for a potent...
Linear temperature-to-frequency – Circuit Schematic
Linear temperature-to-frequency
This circuit provides a linear increase of frequency of 10 Hz/°C over 0-100 °C and can thus be used with logic systems, including microprocessors. Tempera...
Temperature controller – Circuit Schematic
Temperature controller
Temperature control is achieved using the REF-02 +5 V Reference/Thermometer and a CMP-02 Precision Low Input Current Comparator. The CMP-02 turns on a heating e...
Temperature controller – Circuit Schematic
Temperature controller
The sensor is a standard TO-5 or TO-46 package. For surface or air temperature sensing. Small clip-on heat sinks can be used. A simple probe can be made using h...
Single-setpoint temperatre controller – Circuit Schematic
Single-setpoint temperatre controller
The AD590 produces a temperature-dependent voltage across R (C is for filtering noise). Setting R2 produces a scale-zero voltage. For the Celsius scale, make R ...
Heater control – Circuit Schematic
Heater control
This proportional control crystal oven heater uses lead/lag compensation for fast setting. The time constant is changed with R4 and compensating resistor R5...
Boiler control – Circuit Schematic
Boiler control
The purpose of this circuit is to control the water temperature in a hot-water heating system. What it does is to lower the boiler temperature as the outside ai...
Sound operated two-way switch – Circuit Schematic
Sound operated two-way switch
This circuit operates a relay each time a sound of sufficient intensity is made, thus one clap of the hands will switch it one way, a second clap will revert th...
Photoelectric smoke detector – Circuit Schematic
Photoelectric smoke detector
The LED predriver output pulses an external transistor which in turn, switches on the infrared light emitting diode at a very low duty cycle. The desired IR LED...
Ground tester – Circuit Schematic
Ground tester
This circuit checks the reliability of appliances so that the equipment may be used safely. The test circuit must be plugged into a properly wired three termina...