Published:2009/7/17 22:20:00 Author:Jessie
Used to make first audio stage inoperative during no-signal condition in communication receiver.-NBS, Handbook Preferred Circuits Navy Aeronautical Electronic Equipment, Vol. 1, Electron Tube Circuits, 1963, p N12-2. (View)
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Published:2009/7/17 22:19:00 Author:Jessie
Cascaded common-base connection of germanium mesa transistors gives power gain of 40 db, bandwidth of 25 MC, and a noise figure of 3 db. Used between test jig and Hewlett-Packard 342A noise figure meter for measuring noise figure of transistor at 200 Mc. –Texas Instruments Inc., Solid-State Communications, McGraw-Hill, N. Y., 1966, p 345. (View)
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Published:2009/7/17 22:05:00 Author:Jessie
Uses thyratron in magnetic field as basic noise source, to provide azimuth and elevation drive signals for missile radar that simulale actual tracking conditions. Eliminates need for expensive test drones in evaluating missile performance. –C. E. Hendrix, Target Simulator Tests Beam-Rider Missiles, Electronics, 31:5, p 32-35. (View)
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Published:2009/7/10 4:19:00 Author:May
The current range in multimeters, particularly the more inexpensive ones, is restricted by the load limits of the internal shunts to 1 to 2 A. The figure shows how easily a precision heavy-duty resistor from Dale or RCL (0.1Ω;20W;1%) can be used as an external shunt.These resistors were not designed for this purnose, but they are much cheaper than custom-made shunt resistors. The 20-W rating applies only, by the way, if a heatsink is used: without that its rating is only 8W.
The maximum current through the device on a heatsink is about 14A;the larger versions draw up to 17.5A.When mounting the shunt, make sure that the test terminals (as well as the device terminals) are soldered properly, otherwise the resistance of the terminals is added to the shunt. (View)
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Published:2009/7/17 22:04:00 Author:Jessie
Uses conventional noise diode in shielded head. Transistor series regulator with zener diode improves performance when making noise figure measurements of communications receivers.-H. Olson and H. Howard, Noise Figure Measurement Fundamentals, Electronic Technician, November 1965, p 63-66 and 108. (View)
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Published:2009/7/10 4:17:00 Author:May
The output ofthis circuit will be a voltage that is equal to the peak of the input. D1 and C1 detect thepeak voltage and this is read by the IC2 voltage follower. (View)
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Published:2009/7/10 4:17:00 Author:May
Converts counter into digital capacitance meter for measuring valuesclown to around 5 pF with better than 1% accuracy. Three ranges give full-scale values of 99,999 pF, 0,99999 μF, and 9.9999μF. Positive-going countenable command from frequency counter, applied to point A of gate U2A, removes short-circuit from unknown capacitor CX and enables gate U2C. Capacitor charges exponentially through R1 and R2 (range 1) to voltage at which threshold comparator at U1 makes flip4lop change state, shorting CX and disabling gate U2C. During charge time, 1-MHz pulses are applied to counter input. Counter reading then corresponds to capacitor value . C1 is 18 pF.R1 is 860K,R2 is 100K,R3 is 86K,R4 is 10K,R5 is 8.6K,R6 is 1K,and U2 is 7400 quad NAND gate.-R.F. Kramer,Using a Frequency Counteras a Capacitance Meter,QST. Aug 1977, p 19-22. (View)
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Published:2009/7/10 4:16:00 Author:May
Low input bias current of Natiortal LH0052 opamp makes it suitable for applioations requiring long time con stants. R1 is selected so total leakage current at summing mode is sufficiently smaller than sig-nal current to ensure required accuracy. R2 is included to protect input circuit during reset ransient but can be omitted for low-speed applications. R3, used to balance resistance in inputs, should be equal to sum of R2 and 100-ohm resistance of reset switch.- Linear Applications, Vol. 1, National Semiconductor, Santa Clara, CA, 1973, AN-63, p 1-12.
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Published:2009/7/10 4:16:00 Author:May
IC1 produces a full-scale reading on M1 when pin 3 has a 10m Vdc level on it, as determined by R7 and R8. R1 through R4 are shunts that produce a 10-mV drop for the desired full-scale range. R9 zeros the meter. (View)
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Published:2009/7/19 21:42:00 Author:Jessie
Uses Two transistors in integrating circuit and pentode recorder drive. Output of counting-rate mvbr Q1-Q2 is 4.5-V, 260.microsec square pulse that charges integrating capacitor C1 through D2.-F. E. Armstrong and E. A. Pavelka, Monitoring Radioisotope Tracers in Industry, Electronics, 32:26, p 42-43. (View)
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Published:2009/7/19 21:42:00 Author:Jessie
This circuit shows an ICL7107 connected to measure ratiometric values of quad load cells, and to display the results on a 31/2-digit LED. Direct connections between the ICL7107 and the LED are shown in Fig. 12-10B. The resistor values with the load-cell bridge are determined by the desired sensitivity. (View)
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Published:2009/7/10 4:16:00 Author:May
Direct-reading meter gives capacitance values in five ranges, all using same 0-100 scale on 100-μA meter.Operates from three penlight cells. To calibrate, connect known capacitor to jack, close S2, and adiusttrimmer potfor each rangein turn to give correct indication of capacitor value on meter.-C. Green, Build This Easy Capacitor Meter, Modem Electronics, Aug. 1978, p 78-79. (View)
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Published:2009/7/19 21:42:00 Author:Jessie
Depends on harmonic frequency conversion. Oscillator Q1 and amplifier Q2 deliver 153 mw at 250 Mc to coaxial matching section. Despite conversion loss of 11.8 db in 8th-harmonic generator D1, output of 10 mw at 2,000 Mc appears across 50-ohm bolometer.-M. M. Fortini and J. Vilms, Solid-State Generator for Microwave Power, Electronics, 32:36, p 42-43. (View)
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Published:2009/7/19 21:41:00 Author:Jessie
Used to correlate cosmic radiation intensity with other ionospheric and geomagnetic phenomenom. G-M counter provides negative pulse that is differentiated, shaped, and amplified in circuits similar to that of ion chamber. Counter rate is scaled down by 9-stage binary sealer before square wave output is fed to telemetering unit.-L. E. Peter-son R. L. Howard, and J. R. Winckler, Bal-loon Gas Monitors Cosmic Radiation, Electronits, 31:45, p 76-79. (View)
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Published:2009/7/19 21:41:00 Author:Jessie
National LM195 power transistor, used with LM105 regulator, provides full overload protection. Load regulation is better than 2 mV. Circuit requires only 2-V differential between input and output voltages.-R. Dob-kin, Fast IC Power Transistor with Thermal Protection, National Semiconductor, Santa Clara, CA, 1974, AN-110, p 5. (View)
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Published:2009/7/19 21:41:00 Author:Jessie
In this circuit, the XR-2207 oscillator produces a sequence of tones by oscillating at a frequency set by C1 and resistors R1 through R6 (which sot the frequency or pitch of the output tone sequence). The XR-2240 counter/timer generates pseudo-random pulse patterns by selectively counting down the time-base frequency. The outputs of XR-2240 (pins 1 through 8) activate the timing resistors R1 through R6 of XR-2207, which convert the binary pulse patterns to tones. C3 and R0 set the beat or tempo of the music. The output tone sequence continues for about 1 to 2 minutes (depending on the beat ) and then repeats. The XR-2240 resets to zero when power is applied, so the tone sequence (or music) always starts from the same point when the synthesizer is turned on. (View)
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Published:2009/7/19 21:40:00 Author:Jessie
Q1 is Colpitts oscillator at 5 kc and Q2-Q3 is push-pull complementary-emitter amplifier with unity voltage gain. Either switch shorts amplifier, thereby increasing tuning capacitance enough to shift frequency 1 kc.-N. C. Hekimian, Getting Rid of Transients in Frequency-Shift Keying, Electronics, 35:45, p 58-59. (View)
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Published:2009/7/19 21:39:00 Author:Jessie
Voltage follower using an ECG915 operational amplifier. Output is taken on pin 6 (courtesy GTE Sylvania Incorporated). (View)
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Published:2009/7/10 4:15:00 Author:May
This circuit looks at the time an incoming pulse is high. If the incoming pulse is shorter than the adjusted (VAR1) pulse, the output of U1B is high. Values are shown for a 1-to 2-μs pulse. (View)
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Published:2009/7/10 4:15:00 Author:May
This solid-state switch senses and interrupts an overcurrent condition within 2μs. I1 allows the circuit to float. IC1 runs at 150 kHz and full-wave doubler D1/D2 provides 15 V to the gate of Q1. An overcurrent sensed across R1 triggers Q3, removes gate bias from Q1, and opens the circuit formed by the full-wave bridge and Q1. C1 and R3 allow the circuit to handle surges.
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