Circuit Diagram

MULTIPLE_INPUT__OVERVOLTAGE__ALARM

Published:2009/7/9 23:27:00 Author:May

Lamp load of each silicon-contralled switch lights when its input exceeds threshold voliage,to identify input that is responsible for pulling In relay that sounds alarm or shutsdown equipment Lamps aIso serve to suppress rate effect－R.A.Stasior How to suppress Rale Effect in PNPN Devices,Electronics,37:2, p 30－33.   (View)

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VISABLE_VOLTAGE_INDICATOR

Published:2009/7/9 23:26:00 Author:May

  (View)

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RECORDING_SAWTOOTH_CONTROLLING_FLIP_FLOP

Published:2009/7/20 2:06:00 Author:Jessie

Used for sawtooth generator of magnetic drum recording system.-H. L. Daniels and D. K. Sampson, Magnetic Drum Provides Analog Time Delay, Electronics, 32:6, p 44-47.   (View)

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VHF_INTRUSION_ALARM

Published:2009/7/9 23:25:00 Author:May

Based on fact that object moving toward or away from antenna causes phase relationship of radiated and reflected waves to shift through 2 pi radians at antenna for each half-wave length of movement. Varying phase changes amplitude of oscillation, detected by circuit and used to turn on alarm. Drift in oscillator grid voltage activates timing motor which adjusts degree of coupling between oscillator tank and antenna, to make alarm self-adjusting.-G. A.Whitlow, VHF Intrusion Alarm is Self-Adiusting, Electronics, 3235, p 62-66.   (View)

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WIDE_RANGE_AC_VOLTMETER

Published:2009/7/9 23:24:00 Author:May

In this circuit, a diode bridge is used as a meter rectifier. The offset voltage is compensated for by the op amp, since the bridge is in the feedback network.   (View)

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SINE_WAVE_TUNNEL_DIODE_1

Published:2009/7/20 2:05:00 Author:Jessie

Series filter selects desired frequency and rejects harmonics from pulse-shaped output of basic tunnel-diode relaxation oscillator. Values shown give 0.45 Mc, constant within 0.05 Mc over bias range of 100 to 400 mv.-Wen-Hsiung Ko, Designing Tunnel Diode Oscillators, Electronics, 34:6, p 68-72.   (View)

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VU_RECORDER

Published:2009/7/20 2:05:00 Author:Jessie

Used to provide permanent records of broadcast speech levels and for checking audio network circuits. Circuit has same rise time, overshoot, frequency response, and recliner characteristics as standard Vu meter.-D. H. McRae, Vu Recorder Has Standard Response, Electronics, 31:17, p 78-82.   (View)

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SCR_CAPACITOR_TURN_OFF_CIRCUIT

Published:2009/7/9 23:24:00 Author:May

After the SCR tums on, C1 charges up to almost the full supply voltage via R3 and the anode of the SCR. When S2 is subsequently closed, it clamps the positive end of C1 to ground, and the charge on C1 forces the anode of the SCR to swing negative momentarily, thereby reverse-biasing the SCR and causing it to tum off. The capacitor's charge bleeds away rapidly, but it has to hold the SCR's anode negative for only a few ps to ensure turn-off. C1 must be a nonpolarized type.   (View)

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CASSETTE_MOTOR_SPEED_CALIBRATOR

Published:2009/7/9 23:24:00 Author:May

This frequency/voltage converter enables calibrations of cassette-deck speed. It records a steady 1-kHz tone on the cassette deck, and monitors the frequency on the converter. Then play the tone back and adjust the motor speed until you get the same frequency reading on the converter. The frequency/voltage converter can drive an analog meter to indicate small variations in tape speed.   (View)

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471_MC_TUNNEL_DIODE_CRYSTAL_OSCILLATOR

Published:2009/7/20 2:04:00 Author:Jessie

Used in Fire Department service. 0perates within tolerance of quartz crystal from -55 to +85℃ and bias range of 110 to 150 mv for Citizens Band service.- Transistor Manual, Seventh Edition, General Electric Co., 1964, p 353.   (View)

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CHRISTMAS_LIGHT_DRIVER

Published:2009/7/9 23:23:00 Author:May

This circuit will enable a CM0S logic chip, such as a 4017 decode driver, to control a string of Christ-mas lights or other lighting. The triac should be rated at 200V and 3A or higher. The 4017 should be powered from at least 10V to ensure adequate drive to the optoisolator.   (View)

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COMPUTER_FAULT_ALARM

Published:2009/7/9 23:22:00 Author:May

AudibIe alarm system gives distinctive indication of fault loccttion in digitcd computer and data processing equipment. Hom cnd collision signcd sounds are generctted by electronic circuits shown, for monitoring two circuits. Mixing those two signals produces battle stations sound for monitoring third circuit.-S. Fierston, Alarm Circuit Warns of Faults in Digital Systems, Electronics, 32:27, p 48-49.   (View)

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10000_1_KV_PULSES_PER_SECOND

Published:2009/7/20 2:03:00 Author:Jessie

Four-layer diode D3 discharges C1 through pulse transformer and transistor Q1 prevents diode front remaining in conducting state. Used in electrographic recorder.-N. C. Hekimian and P. M. Schmitz, Four-Layer Diode Triggers High-Voltage Pulse Generator, Electronics, 34:26, p 84-85.   (View)

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PEAK_PROGRAM_DETECTOR

Published:2009/7/9 23:22:00 Author:May

This circuit will allow a multimeter to display the positive or negative peaks of an incoming signal. A 741, IC1, is used in the noninverting mode with R1 defining the input impedance. D1 or D2 will conduct on a positive or negative peak, charging C2 until the inverting input is at the same dc level as the incoming peak. This level will maintain the voltage until a higher peak is detected, then this will be stored by C2. Another 741, IC2, prevents loading by the multimeter. Connected in the noninverting mode as a unity gain buffer, output impedance is less than 1 Ω. This circuit has a useful frequency response from 10 Hz to 100 kHz at ± 1 dB. High linearity is ensured by placing the diodes in the feedback loop of IC1, effectively compensating for the 0.6 V bias that these components require.   (View)

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TIMER_IS_AUTOPATCH_KEYER

Published:2009/7/20 2:03:00 Author:Jessie

Simple keyer oscillator using NE555 timer was designed for autopatch in repeater having decoder bandpass from 2980 to 3080 Hz. Adjust R2 to 3042 Hz. 0ut-put options for loudspeaker and microphone are shown. Adjust R3 for required input/output level; use variable resistor if desired. Normally closed keyer contacts can also be connected between pin 7 and ground. Supply can be 9-V transistor radio battery.-E. Noll, Circuits and Techniques, Ham Radio, April 1976, p 40-43.   (View)

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CRYSTAL_OR_CAPACITOR_OSCILLATOR

Published:2009/7/20 2:02:00 Author:Jessie

Gives high stability from 800 kc to 3 Mc, from 0 to 65℃ with either crystal or capacitor. Optimum operating frequency can be found and utilized by changing capacitor value C1 in range up to 500 pf, while awaiting delivery of CT-cut crystal at desired frequency. -T. Asai, Crystal-or-capacitor Oscillator, EEE, 12:3, p 72.   (View)

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STALLED_OUTPUT_DETECTOR

Published:2009/7/9 23:22:00 Author:May

This circuit can be used to detect a stuck out-put or node in a circuit, or a loss of data or pulses.The pulse train charges C1 and biases Q1 on, which lights the LED. If the input remains high, Q2 extin-guishes the LED.   (View)

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SIX_ACCESS_TONES

Published:2009/7/20 2:02:00 Author:Jessie

Provides 0.4-s bursts at choice of six audio frequencies, for access to up to six different repeaters. Value of C1 in transistor circuit determines duration of burst. AF oscillator uses Signetics NE566V phase-locked loop, with tone frequencies determined by C1 and R1 plus R2 through R7. To adjust initially, remove Q1 from circuit so oscillator runs continuously, connect frequency counter to junction of 0.05-pF capacitor and 1-megohm resistor, set all pots at minimum, ad just R1 for 2500 Hz, set selector switch to position 1, and adjust corresponding control for desired frequency.Repeat for other pots.-G. M. Dickson, A Tone-Burst Generator for Repeater Access, QST, April 1974, p 30-31.   (View)

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ALARM_LAMP_DRIVER

Published:2009/7/9 23:21:00 Author:May

Lamp receives power only when combination of signcds from binary stages and mvbr is correct combination of polarities to represent microwave system fctdt to be indicated by remotely located lamp.-J.B. Bullock, Pulse-Coded Foult Alarm in Microwave Systems, Electronics, 33:1, p 82-84.   (View)

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DEGLITCHER

Published:2009/7/9 23:21:00 Author:May

Glitch has been a universal slang expression among electronics people for an unwanted transient con-dition. In D/A converters, the word has achieved semiofficial status for an output transient, which occurs when the digital input addressed is changed. The sample/hold amplifier does double duty, serving as a buffer amplifier as well as a glitch remover, delaying the output by 1/2-clock cycle. The sample/hold can be used to remove many other types of glitches in a system. If a delayed sample pulse is required, it can be generated using a dual monostable multivibrator IC.   (View)

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