Published:2009/7/21 7:48:00 Author:Jessie
Grounded-base Colpitts oscillator uses series-mode crystal with driver and output stage. Current drain is only 1.5 amp from storage battery. No converter is required. Output is 13-w rms carrier.-R. J. Brubaker, An All. Solid-State Marine Band Transmitter, Motorola Application Note AN-156, Feb. 1966. (View)
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Published:2009/7/21 7:48:00 Author:Jessie
Simple full-wave power control circuit using a triac (courtesy Motorola Semiconductor Products Inc.). (View)
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Published:2009/7/21 7:47:00 Author:Jessie
Color TV 3.58 MHz crystal oscillator using adual-gate MOSFET (courtesy Texas Instruments Incorporated). (View)
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Published:2009/7/21 7:47:00 Author:Jessie
Simple DC power control circuit using an SCR (courtesy Motorola Semiconductor Products Inc.). (View)
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Published:2009/7/21 7:47:00 Author:Jessie
Provides crystal-controlled output frequency in 100-kc steps at 1-sec intervals from 31.05 to 54.95 Mc, with each step an odd multiple of 50 kc. Used to control pulse transmitter and receiver at widely separated locations, for observation of mutual propagation conditions between the two points. Frequency control of r-f oscillator is obtained by mixing sample r-f signal with 1-Mc reference and comparing components of product with 50-kc pulse spectrum supplied by pulse generator V6B.-Frequency Stepper for Radio Propagation Tests, Electronics, 32:4, p 44-46. (View)
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Published:2009/7/21 7:46:00 Author:Jessie
TV vertical deflection system (courtesy GTE Sylvania Incorporated). (View)
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Published:2009/7/21 7:46:00 Author:Jessie
Full-wave average voltage feedback control circuit for a 600-watt load (courtesy Motorola Semiconductor Products Inc.). (View)
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Published:2009/7/21 7:45:00 Author:Jessie
Input is conventional push-pull configuration providing out-of-phase signals for both transistors, but for output circuit both transistors operate in parallel into standard pi network. This cancels fundamental and odd-order harmonics, leaving only second harmonic predominating in output circuit. Transistors can be 2N1692.-W. A. Rheinfelder, Choosing the Best Transmitter Output Stage, EEE, 11:10, p 48-53.
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Published:2009/7/21 7:59:00 Author:Jessie
240-volt triac control circuit driven by two MOC3011 optically coupled tdac drivers (courtesy Motorola Semiconductor Products Inc.).
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Published:2009/7/21 7:59:00 Author:Jessie
Trigger generator for scr modulator uses, two-layer and four-layer diodes to provide pulse burst, repetition rates up to 25 kc.-H.G. Heard, Controlled Rectifier Produces Quarter-Megatwatt Pulse Power, Electronics, 34:25, P 54-55. (View)
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Published:2009/7/21 7:57:00 Author:Jessie
Complete FM/TV 4.5 MHz sound channel using an ECG1045 14-pin DIP. Audio power output is 1.5 watts. The ECG1045 contains a three-state high-gain directional IF amplifier and a ratio detector. IF transformers and the AF output transformer are standard items and can be purchased at Radio Shack. This circuit can be modified for 10.7 MHz operation by selecting the proper IF transformers (courtesy GTE Sylvania Incorporated). (View)
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Published:2009/7/21 7:57:00 Author:Jessie
RMSopen-loop voltage compensator (regulator) for small conduction angles. This circuit provides an output of 110/115 ±2.5 volts at 600 watts for an input of 200 to 260 volts. This circuit is suitable for applications requiring a conduction angle of less than 90 (courtesy Motorola Semiconductor Products Inc.). (View)
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Published:2009/7/21 7:57:00 Author:Jessie
Dual triggers supply alternating pulses for driving d-c to d-c voltage converter connected to A and B. Frequency of triggering can be adjusted from 650 to 900 cps by varying base-to-base voltages of unijunction transistors.-T. Wilson, Voltage Controls Dual-Pulse SCR Trigger, Electronics, 37:28, p 62-63. (View)
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Published:2009/7/21 7:56:00 Author:Jessie
Proportional controller for heater using two op amps. The integrating error amplifier holds the heater current pulse width at a sustaining value at equilibrium (courtesy Burr-Brown Research Corporation). (View)
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Published:2009/7/21 7:55:00 Author:Jessie
Unlike Schmitt trigger, both transistors stop conduction when input is removed.-L. L. Kleinberg, Complementary Shaper Replaces Schmitt Trigger, Electronics, 37:26, p 66. (View)
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Published:2009/7/7 9:29:00 Author:May
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Published:2009/7/7 9:27:00 Author:May
Amplifier A increases the microphone's output to a usable level. The output signal is fed to op amp B, which inverts the signal 180°. A balance-control potentiometer connects across the outputs of amplifiers A and B. If an audio tone is fed into the microphone and the balance potentiometer's wiper is all the way over to the A output position, the tone will be heard at a high level. As the wiper is rotated toward the B output, the audio level will decrease until it just about disappears near the center of the potentiometer's range. As you continue to rotate the wiper, the signal will begin to increase once again.With the balance control set for a minimal output, the intercom's tendency to self-oscillate from acoustical feedback between the microphone and speaker is kept to a minimum. The microphone's ampli-fted signal at A's output is fed to the other intercom through the audio in/out cable. Since both intercom units are alike, the audio information coming from one unit feeds the other at the input of op amp B. The incoming audio is amplified slightly by op amp B and the output signal is sufficiently increased by the power amp to drive the speaker. (View)
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Published:2009/7/7 9:25:00 Author:May
This intercom uses a single audio IC as a two-way amplifier, and the speakers as microphones. A single 6-V supply provides adequate audio volume. (View)
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Published:2009/7/7 9:24:00 Author:May
This system uses μA759 audio IC devices and a common connection between the preamps as an inter-connect. Either mike can drive either speaker. Duplex operation is possible with only one cable (two wires). (View)
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Published:2009/7/7 9:21:00 Author:May
When activated, the transmitter sends out a 49.890-MHz, AM rf carrier. The receiver detects, ampli-fies, and decodes the rf signal, which, in turn, activates a piezo buzzer. The receiver is small enough to carry in a pocket or sit on your workbench, The transmitter is also small and fits easily into a pocket for quick access. (View)
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