Published:2009/7/22 22:08:00 Author:Jessie
In many audio applications,it is desirable to provide a mixer tocombine or select several inputs,Such applications include public-address systems,where more than one microphone is used,tape recorders,hi-fi phonographs,guitar amplifiers,etc.This circuit provides for mlxlng of 600-Ω dynamic microphones, each with an output level of 10 mV The circuit operates from a 24-V Supply and delivers 5-V output,with a dynamic range of 80 dB. (View)
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Published:2009/7/22 22:00:00 Author:Jessie
This circuit shows a 4N26 that is used as a diode/diode coupler. The 4N26 emitter is left open, the load resistor is connected between base and ground, and the collector is tied to the supply. Using the 4N26 in this way reduces the switching time from about 2 or 3 μs to 100 ns. (View)
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Published:2009/7/22 4:07:00 Author:Jessie
This circuit provides a 7- to 35-W output, depending on power source and component values (as shown), with overload protection. Figures 1-18B and 1-18C show the PC-board layout and performance characteristics, respectively. (View)
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Published:2009/7/22 4:05:00 Author:Jessie
This circuit provides a 3- or 5-W output, depending on power source and component values, with an npn driver, and overload protection. Figures 1-17B and 1-17C show the PC-board layout and performance characteristics, respectiVely.
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Published:2009/7/22 4:03:00 Author:Jessie
This circuit provides a 3- or 5-W output, depending on power source and component values, with a pnp driver and overload protection. Figures 1-16B and 1-16C show the PC-board layout and performance characteristics, respectively. (View)
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Published:2009/7/22 4:01:00 Author:Jessie
This circuit makes optimum use of economy transistors in discrete-component amplifiers that will operate safely under any usable load conditions, including shorts. Figures 1-15B, 1-15C, and 1-15D show the transistor complement, resistor values/power-supply voltages, and heatsink requirements, respectively, for various power outputs from 35 to 100 W. Input sensitivity is 1 Vrms into 10 kΩ for full-rated output power. Frequency response is less than 3-dB rolloff from 10 Hz to 100 kHz, referenced to t kHz. Power bandwidth is the full-rated output power ±2 dB from 20 Hz to 20 kHz. Figures 1- 15E and 1- 15F show the load sensitivity and power bandwidth. Total harmonic distortion (THD) is less than 0.2% at any power level between 100 mW and full-rated output and at any frequency between 20 Hz and 20 kHz. Inter modulation distortion is less than 0.2% at any power level from 100 mW to the full-rated output (60 Hz and 7 kHz mixed 4 to 1 )
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Published:2009/7/22 5:27:00 Author:Jessie
The JFET provides both high input impedance and low noise to buffer an op-amp feedback-type tone control. (View)
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Published:2009/7/22 4:32:00 Author:Jessie
This circuit shows an LM108 amplifier for high-impedance ac transducers, such as a piezoelectric accelerometer. The circuit has input resistance that is much greater than the dc return resistor values. This is accomplished by bootstrapping the resistors to the output. With such an arrangement, the lower cutoff frequency of a capacitive transducer is determined more by the RC output of R1 and C1 than by resistor values and the equivalent capacitance of the transducer. (View)
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Published:2009/7/22 4:29:00 Author:Jessie
This circuit has boost and cut specifications similar to that of Fig. 1-22.The wideband gain is equal to the ultimate boost or cut, plus one (in this case a gain of 11). For a 20-dB boost and cut, the input loading is essentially equal to the resistance from terminal 3 to ground. (View)
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Published:2009/7/22 4:28:00 Author:Jessie
This circuit provides unity gain at midband and uses standard linear potentiometers. Bass/treble, boost, and cut are ±15 dB at 100 Hz and 10 kHz, respectively. Full peak-to-peak output is available up to at least 20 kHz. Amplifier gain is -3 dB down from the flat position (70 kHz). (View)
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Published:2009/7/22 4:25:00 Author:Jessie
This circuit has a true complementary-symmetry output with a programmable IC amplifier input. (View)
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Published:2009/7/22 4:21:00 Author:Jessie
This circuit provides a 15-, 20-, or 25-W output, depending on the power source and component values (as shown), with overload protection, using Darlingtons in the output stages. Figures 1-20B and 1-20C show the PC-board layout and performance characteristics, respectively. (View)
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Published:2009/7/22 20:34:00 Author:Jessie
This circuit requires only 0.1 second for turn-on, Compare to Fig. 1-29.When recording, the frequency response is the complement of the NAB playback equalization, making the composite record and playback response flat (Fig.1 -30B). (View)
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Published:2009/7/22 20:20:00 Author:Jessie
This circuit requires about 5 seconds to turn on (for the gain and supply voltages shown). The turn-on time is approximately
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Published:2009/7/22 20:18:00 Author:Jessie
Sometimes called the JFET μ amp, this circuit provides a very low-power, high-gain amplifying function. Because μ of a JFET increases as drain current decreases, the lower drain current is, the more gain you get. However, dynamic range is sacrificed with increasing gain. (View)
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Published:2009/7/22 20:16:00 Author:Jessie
This preamplifier provides proper loading to a reluctance-type phono cartridge. The circuit provides about 25 dB of gain at 1kHz (2.2-mV input for 100-mV output), and features S+ S/N ratio of better than -70 dB (referenced to 10-mV input at 1kHz). The feedback provides for RIAA equalization with a dynamic range of 84 dB (reference to 1kHz). (View)
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Published:2009/7/22 21:15:00 Author:Jessie
This circuit requires only 0.1 second for turn-on, Compare to Fig. 1-29.When recording, the frequency response is the complement of the NAB playback equalization, making the composite record and playback response flat (Fig.1 -30B). (View)
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Published:2009/7/22 22:11:00 Author:Jessie
This circuit shows an LM380 power-amplifier IC used as a phono amplifier The circuit has a voltage-divider volume control, with high-frequency rolloff tone control, and provides about 2.5 W to an 8-Ω speaker. (View)
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Published:2009/7/23 21:10:00 Author:Jessie
This amplifier operates from a +98-V supply (the rectified line voltage). Such amplifiers are often found in consumer products. Virtually any high-voltage transistor (capable of about 100 V from collector to emitter) can be used for Q1, which is biased and controlled by the LM3900 Norton amplifier (chapter 11). The magnitude of the dc biasing voltage, which appears across the emitter resistor of Q1 is controlled by the resistor between the (-) input of the LM3900 and ground. (View)
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Published:2009/7/23 20:22:00 Author:Jessie
The resistors in the output lines are included to isolate reflections from unterminated lines. If the line characteristics are known, the resistors can be deleted. To meet NTSC gain-phase requirements, a small-value boost resistor is used. Figures 3-27B and 3-27C show the LT1010 characteristics. (View)
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