Circuit Diagram

25_500_kHz_TO_35_4_MHz

Published:2009/7/16 3:27:00 Author:Jessie

When receiver is tuned to 3.5 MHz and converter is peaked for loudest signal, combination is tuning 25.kHz range. With receiver tuned to 4 MHz converter gives coverage at 500 kHz.--Circuits, 73 Magazine, May 1977, p 19.   (View)

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IR_WIDTH_GAGE_TRANSLATOR

Published:2009/7/16 3:26:00 Author:Jessie

Combined signal output from main amplifier of infrared gage triggers bistable mvbr V7, output of which is rectangular pulse whose width is proportional to steel strip width. Pulse is clamped and amplified by V8 and passed to comparator V9, which provides output proportional in amplitude to width of input pulse.-F. J. Dunks, Infrared Gage Measures Hot Steel Strip Width, Electronics, 33:43, p 65-67.   (View)

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VFO_CONVERTER

Published:2009/7/16 3:25:00 Author:Jessie

Used in solid-state five-band communication receiver. VFO input (5-5.5 MHz) goes directly to amplifiers Q5 and Q6 when bandswitch is on 3.5 or 14 MHz. When VFO signal is applied to balanced mixer CR7-CR10, product is at 9 MHz. Diodes should be carefully selected for equal voltage drops t20 mV at various current values such as 0.75, 2, 10, and 20 mA. When bandswitch is on 7, 21, or 28 MHz, VFO signal is mixed with output of FET crystal oscillator and filtered before being applied to Q5 and Q6. FET oscillators a1-a4 are energized by +12 V from bandswitch, with diodes CR1-CR4 selecting output. Crystals are parallel-resonant with 32-pF Load. Y2, Y3, and Y4 are third-overtone type.-P. Moroni, Solid-State Communications Receiver, Ham Radio, Oct. 1975, p 32-41.   (View)

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INFRARED_HOT_ENGINE_DETECTOR_1

Published:2009/7/16 3:25:00 Author:Jessie

Hot-engine alarm using only two transistors and an car resets parking meter to zero when lead sulfide infrared detector senses engine heal as parked car starts. Circuit combines Colpitts oscillator with Schmitt trigger.-W. E. Osborne, Farewell To Free Time On City Parking Meters, Electronics, 37:32, p 72.-74.   (View)

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AUTO_LOCKING_GATE_FOR_TACHOME_DISPLAY

Published:2009/7/16 3:24:00 Author:Jessie

Permits pulses to pass to display unit during gating period. Display can be held for 5, 10, or 15 sec by switching different capacitors into delay Additional 200-millisec delay gives time for counting tubes to return to zero.-J. K, Goodwin, Digital Tachometer Aids in Turbine Design, Elecfronics,32:15, p 58-61.   (View)

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High-current Voltage Regulator Tube Circuit

Published:2011/7/17 21:08:00 Author:Felicity | Keyword: High-current, Voltage Regulator, Tube Circuit

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BATTERY_ORANKING_TESTER

Published:2009/7/13 4:43:00 Author:May

Need to discover if your battery is weak or if your starter's windings are shorted? This meter will display how low your battery voltage drops during a start. The circuit is a negative-peak reading voltmeter.   (View)

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FREQUENCY_PERIOD_EVENT_TIME

Published:2009/7/13 4:43:00 Author:May

Universal counter with 10-MHz maximum frequency pro-vides multiple functions with minimum number of components. Range of time period measure-ments is 0.5 μs to 10 s. Includes 10-MHz crystal oscillator, multiplex timing with inter digit and leading-zero blanking, as well as overflow indication. Decimal position is selectable. Eight-digit multiplexed LED display outputs of IC can switch up to 250 mA per digit for handling large displays. Maximum supply voltage is 6 V.-Low Cost Universal Counter Performs Wide Range of Functions, Computer Design, Aug. 1978, p 168 and 170.   (View)

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10_LED_BAR_GRAPH_INDICATOR_CIRCUIT

Published:2009/7/13 4:43:00 Author:May

The solid-state level indicator consists of a string of 10 LEDs in one package. With a low-level signal input, all LEDs are off. As the signal increases, more LEDs light up, until finally all10 are turned on to indicate the maximum level. The heart of the circuit shown in this figure is the National Semiconductor LM3915. The LM3915 contains a precision voltage reference, resistor divider chain, and 10 comparators to drive the LEDs. This IC also contains current-limiting circuitry that limits the brightness of the LEDs without the need for separate resistors, and logic to select either a bar graph or a moving-dot display.   (View)

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PIEZOELECTRIC_DRIVER_CIRCUIT

Published:2009/7/13 4:42:00 Author:May

Three-terminal piezoelectric elements are typically driven by transistor circuits (A) or logic gates (B).   (View)

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ELECTRICAL_SYSTEM_ANALYZER

Published:2009/7/13 4:41:00 Author:May

The automotive electrical diagnostic system is built around a Maxim MAX8214ACPE five-stage voltage comparator, which contains a built-in 1.25-V precision reference and on-board logic that allows the outputs of two of the comparators to be inverted.   (View)

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DIGITAL_COUNTING_DEMONSTRATOR

Published:2009/7/13 4:41:00 Author:May

555 timer serves as dock for driving RS7490 decade counter feeding RS7447 BCD to 7-segment decoder that drives 7-segment digital display. R1 is adjusted to give clock frequency that makes display cycle slowly through digits 0-9 and repeat, for classroom demonstrations. －F. M. Mims, Integrated Circuit Projects, vol 6, Radio Shack, Fort Worth, TX, 1977, p 53－63   (View)

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BALANCED_INPUT_MIXER

Published:2009/7/13 4:40:00 Author:May

Used with frequency-independent antennas to provide noise cancellation as balanced-input converter.-C. Strother, Jr. and C. R. Lundquist, Balinverter-Frequency-Insensitive Balanced Converter, Electronics, 35:44, p46-47.   (View)

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Tube Regulator Circuit

Published:2011/7/17 21:07:00 Author:Felicity | Keyword: Tube Regulator Circuit

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DENSITY_AND_EXPOSURE

Published:2009/7/13 4:40:00 Author:May

Circuit converts transmission parameter of spectrophotometer to more useful density parameter, which in turn can be converted to exposure parameter. Optical Electronics 2357 opamps at input provide 90-dB dynamic range for DC to 1 kHz or40-dB range for DC to 100 kHz, operating basicallyas current amplifiers. 9827 is used as wideband opamp in unity-gain subtracter configuration. Additional 376 opamps are used only for convening to exposure parameter. Use 1000 ohms for R1 with 10-V full-scale inputs.- Conversion of Transmission to Density and Density to Exposure, Optical Electronics, Tucson, AZ, Application Tip 10133.   (View)

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VOLUME_UNIT_DISPLAY_AND_ALARM_1

Published:2009/7/13 4:39:00 Author:May

The concept is achieved by using two input modules, namely the sound input circuit and the signal mixer circuit, and selecting between them by means of a switch. The signal is then processed by an integrated circuit (IC3) and associated components, which convert a rising and falling voltage into a rising and falling LED display. The buzzer output module is connected so that when the appropriate LED lights, the buzzer sounds, indicating the excess level warning.   (View)

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PHASE_CONTROLLED_DIMMER

Published:2009/7/13 4:39:00 Author:May

Mullard TCA280A trigger modulels connected to comρare amplitude of ramp waveform with controllable DC voltage in difference amplifier,At point of coincidence, trigger pulse is produced in output amplifier for triggering triac that controls lamp load. Choice of triac depends on load.Values shown for C4 and R9 give 100-μs pulse—''TCA280A Tigger IC for Thyristors and Triacs, ''Mullard, London, 1975,Technical Note19,TP 1490,p 12.   (View)

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CALCULATOR_COUNTS_BY_4s

Published:2009/7/13 4:39:00 Author:May

Connection shown for National MM5736 calculator chip counts either up or down by 4s, as might be required for keeping track of inventory in bin when parts are packaged in groups of 4. To count by numbers other than 1, desired number is entered into calculator during manual start operation. When S2 is pushed, counter adds 4 to accumulated total. When S3 is pushed, counter subtracts 4 from accumulated total. Logic ele-ments provide self-starting action of counter. -M. Watts, Calculator Chip Makes a Counter, National Semiconductor, Santa Clara, CA, 1974 AN-112,p5.   (View)

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MULTIPLE_TIMER_FOR_PRINTS

Published:2009/7/13 4:38:00 Author:May

Six independent 2-min timers, each using half of SN7473N IC, are set in sequence by unique input switch as sheets of exposed paper are inserted in developer at about 20-s intervals. When capacity of six prints is reached, Tr12 turns on light to tell operator that no more prints should be inserted until control logic activates alarm signifying 2-min time for first sheet inserted. Audible bleep is repeated as each subsequent sheet reaches its 2-min development time. Article gives all circuits and explains operation in detail. Two-input NAND gates (each 1/4 of SN7400N) and inverters (each1/6 of SN7404N) are used to steer reset pulses. Similar twoinput NAND gates are used to form fully compatible input pulses from input switch control, each having correct level, rise time, and fall time, without contact bounce that might cause spurious starting of several timers simultaneously.-R. G. Wicker, Photographic Development Timer, Wireless World, April 1974, p 87-90.   (View)

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High-precision Constant Voltage And Constant Current DC Power Supply Circuit

Published:2011/7/17 21:32:00 Author:Felicity | Keyword: High-precision, Constant Voltage, Constant Current, DC Power Supply Circuit

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