Published:2011/8/8 3:13:00 Author:Ecco | Keyword: Digital lock
The digital lock circuit is composed of the password control circuit and sound and alarm circuir, and it is shown in Figure 3-104. Password control circuit consists of password buttons SO-S2, thyristors VTl-VT3, resistors Rl-R3, light-emitting diode VL and solenoid YA. Sound and alarm circuit consists of the error buttons S3-S9, thyristor VW, resistors R4-R8, voice integrated circuit ICl, audio power amplifier integrated circuit IC2, voltage regulator diode VS, capacitors Cl-C5 and the speaker BL. Rl-R4 and R6-R8 use the 1/4W carbon film resistors or metal film resistors; R5 select the 1/2W metal film resistor.
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Published:2011/8/4 1:56:00 Author:Ecco | Keyword: multivibrator, variable duty cycle, Schmitt trigger
It is the multivibrator with variable duty cycle composed of Schmitt trigger CD40106.
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Published:2009/7/14 22:11:00 Author:Jessie
Unknown signal to be analyzed is multiplied independently by each of two output reference signals, A and B. Oscillator uses two 90° phase-shift networks and 180° of phase shift in amplifier. Gain of 0.98 in cathode follower makes circuit accurate over 10:1 frequency range.-T. B. Fryer, Frequency Analyzer Uses Two Reference Signals, Electronics, 32:18, p 56-57. (View)
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Published:2009/7/14 21:36:00 Author:May
Class C Hartley master oscillator serves for synchronizing three basic relaxation oscillators that would otherwise be free-running. Dividers remain locked over temperature range of 0 to 70℃.- Transistor Manual, Seventh Edition, General Electric Co., 1964, p 342. (View)
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Published:2009/7/14 22:40:00 Author:Jessie
Modulator consists of two variable-capacitance diodes in series to r-f and in parallel to audio modulating signals and d-c bias. Frequency deviation is 28 Mc peak-to-peak with modulating signals less thon 28 v and negligible modulating power.-C. Arsem, Wideband F-M with Capacitance Diodes, Electronics, 32:49, p 112-113. (View)
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Published:2009/7/14 22:38:00 Author:Jessie
Combines Q multiplier with Miller effect to produce simple and stable f-m oscillator and modulator.-P. W. Wood, Transistorized F-M Oscillator, Electronics, 32:5, p 64. (View)
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Published:2009/7/14 23:26:00 Author:Jessie
Produces f-m signal output that is directly proportional to applied force, such as stress or pressure resistive-type gage. Operating and band, edge frequencies of oscillator are determined by values of R, L, and C.-W. H. Foster, Strain Gage Oscillator for Flight Testing, Electronics, 31:5, p 40-42. (View)
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Published:2009/7/14 20:48:00 Author:May
PLIERS-4214 differential multipliers eliminate need for opamps in quadrature oscillator in which frequency is controlled by external DC voltage. R3, R4, R5, and D1 form diode limiter, while R1,R2,and C1,provide positive feedback to sustain oscillation,R1 should be about equal to R, R2about 20R, and C1 about 10C. R2 can be readjusted for best compromise between distortion and speed of amplitude buildup.-Y. J. Wong, Design a Low Cost, Low-Distortion, Precision Sine-Wave Oscillator, EDN Magazine, Sept. 20, 1978, p 107-113. (View)
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Published:2009/7/14 23:24:00 Author:Jessie
Wideband frequency modulation of 400-Mc distributed-parameter Colpitts oscillator is obtained with symmetrical transistor in modulator. Q1 is equivalent to two reverse, biased diodes in series for r-f and in parallel with respect to modulating signals and d-c bias.-C. Arsem, Wideband r-m with Capacitance Diodes, Electronics, 32:49, p 112-113. (View)
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Published:2009/7/14 23:23:00 Author:Jessie
Voltage-tunable ferroelectric capacitors are used for tuning as well as for modulating.-T. W. Butler, Jr., Ferroelectrics Tune Electronic Circuits, Electronics, 32;3, p 52-55. (View)
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Published:2009/7/14 23:06:00 Author:Jessie
Video voltage of wide-band f-m receiver is applied to base of silicon tetrode to give voltage-sensitive 100-Mc f-m oscillator in which deviations can be up to 1 Mc without excessive distortion.-S. Kallus, B. Robinovici, and A. Newton, Fitting a Wide.Band Signal Into a Narrow-Band Receiver, Electronics, 36;10, p 47-49. (View)
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Published:2009/7/14 20:39:00 Author:May
Input d-c control voltage required by SiC varistors of voltage-tuned oscillator is boosted by d-c amplifier stages that produce two control voltages (at A and B) for SiC varistors of phase-shift oscillator circuit, changing their a-c resistance and thereby oscillator frequency.-M. Uno, Varistor Network Controls Voltage-Tuned Oscillator, Electronics, 34:30, p 44-47. (View)
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Published:2009/7/14 22:53:00 Author:Jessie
Modulating signal is applied to vat deviation of 60 kc.-N. Downs and B. varactor diode in frequency-determining circuit of telemetering oscillator. Linearity is 2% for deviation of 60 kc.-N. Downs and B. van Sutphin, Solid-State Transmitter Ready for UHF Telemetry, Electronics, 37:17, p 76-80. (View)
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Published:2009/7/14 22:50:00 Author:Jessie
Uses two tunnel-diodes in astable mvbr to give symmetrical square wave output. Used to produce wide frequency swing with respect to center frequency, linearly, when small control voltage is applied.-F. H. Lefrak, Tunnel-Diode Oscillator Expands F.M System's Tunnel-Diode Oscillator Expands F-M System's Channel Capacity, Electronics ,39:1, P 105-109. (View)
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Published:2009/7/14 20:33:00 Author:May
Voltage-variable capacitance tuning diode in series with crystal feedback path of Motorola MC10116 IC gives frequency deviation of about ±50 PPM for 1-MHz crystal when using tuning voltage range of 0-25 VDC. Deviation is greater at higher crystal frequencies.-B. Blood, IC Crystal Con-trolled Oscillators, Motorola, Phoenix, AZ, 1977, AN-417B, p 6.
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Published:2009/7/14 7:59:00 Author:May
Voice-operated ON/OFF switch uses microphone to sense normal back-ground sound. Anything above background threshold preset by R16 energizes relay K for turning on recorder. Circuit provides about 2-s delay after subject stops talking, before releasing relay. Automatic volume control circuit keeps recorded signal essentially constant despite movements of loudspeaker toward or away from microphone.-G. Beard, Automatic Volume and VOX for Your Tape Recorder, Popular Science, Oct. 1973, p 134 and 136. (View)
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Published:2009/7/14 5:09:00 Author:May
Used in high-quality stereo cassette deck operating from AC line or battery. Provides up to 33 VRMS at 50-kHz erase frequency, as required for completely erasing existing recording on tape when recording over it. Supply voltage should be in range of 12-14 V. Article gives all other circuits of cassette deck and describes operation in detail.- J. L. Linsley Hood, Low-Noise, Low-Cost Cassette Deck, Wireless World, Part 1-May 1976, p 36-40 (Part 2-June 1976, p 62-66; Part 3-Aug. 1976, p 55-56) (View)
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Published:2009/7/14 4:58:00 Author:May
Can be driven with linear time base of voltage and used with logarithmic frequency display, as in frequency-response tests Useful range of circuit is four decades Values shown give timing-current range of 10 nA to 100 μA, yielding frequency range of 1 Hz to 10 kHz. Input voltage range of 60 mV per decade is obtained from voltage divider R1-R2 to allow higher and more practical value for actual input voltage to circuit. –W. G. Jung, IC Timer Cookbook, Howard W. Sams, Indianapolis, IN, 1977, p 174-179. (View)
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Published:2009/7/14 4:56:00 Author:May
Changes in control voltage input are used to vary nominal 1-kHz output of CD4007 CMOS voltage-controlled oscillator proportionately. Values of R and C can be changed to obtain other nominal frequencies.-W. J. Prudhomme, CM0S Oscillators, 73 Magazine, July 1977, p 60-63.
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Published:2009/7/14 4:44:00 Author:May
Operates over control-voltage range of +10 mV to +10 V to provide either square or triangle outputs from 5 Hz to 5 kHz, Can be used for instrumentation or electronic music applications.- W. G. Jung, IC Timer Cookbook, Howard W. Sams, Indianapolis, IN, 1977, p 174-179.
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