FONT_face=VerdanaRSUB1_SUB_RSUB2_SUB_–_VSUB1_SUB_VSUB2_SUB_FONT_frequency_converter

Published:2009/7/23 23:44:00 Author:Jessie

Fig, 12-16 This circuit produces an output frequency that is proportional to the ratio of voltages across two external resistors. The circuit has wide application in transducer signal-conditioning (chapter 14). Both R1 and R2 are ground-referred for noise considerations. In this particular circuit, R1 is a platinum resistance sensor and R2 is set at the R1 0℃ value. The circuit may be used with any resistive-based transducer. For negative TC devices, reverse the positions of R1 and R2. The grounded end of R2 allows fine trimming with decade boxes (if necessary to compensate for R1 tolerances at 0°) without excessive noise problems. The grounded side of R1 permits RI to be located at the end of a cable run (again without noise problems). The DAC serves as a simple source of two identical currents (The DAC MSB is set high, with all other bits low). With constant and equal currents, R1 and R2 produce a differential voltage, which is sampled by the LTC1043 switched-capacitor in the normal manner. To trim, place R1 in a 100℃ environment and adjust the full-scale trim for a 1-kHz output. Linear Technology. Linear Applications Handbook, 1990 p. AN14-17.   (View)

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15_A_negative_adjustable_voltage_regulator

Published:2009/7/23 23:44:00 Author:Jessie

The LAS18U is a four-terminal adjustable regulator IC with an output range from -2.6 to -30 V, adjustable from a single pot. Characteristics are shown in Fig. 7-42B, 7-42C, and 7-42D.   (View)

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Wideband_FET_input_composite_buffer_

Published:2009/7/23 23:44:00 Author:Jessie

This composite circuit provides a gain of 0.95 with a full power bandwidth near 50 MHz and a slew rate of 2000 V/μs. Offset is about 5μV. Figure 1-19B shows a delay between input and output of about 4 ns.   (View)

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15_A_negative_fixed_voltage_regulator

Published:2009/7/23 23:43:00 Author:Jessie

The LAS1800 series voltage regulators are ICs that contain all elements necessary for linear regulation (safe-area protection, thermal overload, current limiting, as shown in Fig. 7-42C). Figure 7-42B shows the output voltage and tolerance for the various LAS1800 part numbers. Figure 7-42D shows the absolute maximum ratings.   (View)

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ESUBX_SUB_transfer_function_V_F_converter

Published:2009/7/23 23:43:00 Author:Jessie

Fig. 12-15 This circuit responds exponentially to the input voltage and is ideally suited for electronic music synthesizers. The circuit has a 1-V-in/octave-offrequency-out scale factor, with exponential conformity with 0.13% over a 10-Hz to 20-kHz range, and 150 ppm/℃ drift. Both a pulse output and a ramp output are available (the ramp is used where substantial power at the fundamental frequency is required). To trim, ground the Q3 base and adjust the 2-kΩ potentiometer so that the A3 inverting input is 100 mV above the noninverting input. Remove the ground at Q3. Linear Technotogy Linear Applications Handbook 1990, p AN14-15.   (View)

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Step_down_PWM_switch_mode_regulators

Published:2009/7/23 23:43:00 Author:Jessie

Figure 7-17 shows the MAX724/26 connected as basic step-down converters，Figures 7-18 and 7-19 show the pin configurations．Figure 7-20 shows component suppliers．MAXIM EVALUATION KIT DATA Book， 1994, P. 3-131, 3-131, 3-139.   (View)

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8_A_positive_fixed_voltage_regulator_with_remote_sensing

Published:2009/7/23 23:56:00 Author:Jessie

This circuit uses the LAS3905 IC (Fig.7-50) as a voltage regulator with remote sensing. Characteristics are shown in Fig.7-50B, 7-50C, and 7-50D.   (View)

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D_C_VOLTAGE_COMPARATOR

Published:2009/7/24 Author:Jessie

Compares long-duration sawtooth input with d-c reference and generates pulse when inputs coincide.-R. D. Valentine, D-C Voltage Comparator Circuit Uses Tube and Transistor, Electronics, 34:24, p 66.   (View)

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Negative_output_F_V_converter

Published:2009/7/24 Author:Jessie

Fig. 12-24 This circuit is similar to that of Fig. 12-19, but with an output/buffer op amp connected to provide a negative output voltage. The 1-MΩ offset adjust can be set to accommodate variations in supply voltage (with 0-V output for a grounded or 0-Hz input). Because the offset voltage is taken from the stable 1.9-V reference voltage from pin 2 of the LM331, any supply-voltage shifts cause no output shifts. Although 1-MΩ is shown, the offset potentiometer can have any value between 200 kΩ and 2 MΩ. The optional bypass capacitor C2 (across R5) prevents output noise arising from stray noise pickup at the noninverting input of the op amp. To trim, set the 5-kΩ gain-adjust control for -10-V output with a 10-kHz input. National Semiconductor Linear Applications Handbook 1991 p 1302.   (View)

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_5_V_to_±12_V_±15_V_converter_module

Published:2009/7/23 23:59:00 Author:Jessie

Figure 7-27 shows a MAX1743 3-W converter module that requires no external components. The module supplies 125 mA at 112 V or 100 mA at 115 V. Pin strapping selects 112-V or 115-V operation. Figure 7-28 shows the pin descriptions and operating characteristics. Figure 7-29 shows an optional stand-by mode circuit. MAXIM NEW RELEASES DATA Book, 1994, P. 4-27, 4-29, 4-30.   (View)

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5_A_negative_adjustable_voltage_regulator_with_safe_area_protection

Published:2009/7/23 23:59:00 Author:Jessie

This circuit uses the basic LAS79HG IC and external components to provide safe-operating-area protection. Characteristics are shown in Fig. 7-56B and 7-56C.   (View)

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Basic_F_V_converter_with_temperature_compensation

Published:2009/7/23 23:58:00 Author:Jessie

Pig. 12-23 This circuit is similar to that of Fig. 12-19, but with temperature compensation. RX, D1, and D2 cancel the effect of timing capacitance TC. The manufacturer recommends that the circuit be checked with an oven if TC is critical. Resistance can be added in parallel or series with RX to offset the timing capacitor TC If TC is not critical, use 240 kΩ for RX. Again, set the 5-kΩ gain adjust for 10-V output with a 10-kHz input. National Semiconductor Linear Applications Handbook 1991 p 1301.   (View)

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5_A_negative_adjustable_voltage_regulator_with_remote_sensing_and_current_limiting_at_6_A

Published:2009/7/23 23:58:00 Author:Jessie

This circuit uses the basic LAS79HG IC and external components to provide both remote sensing and current limiting. Characteristics are shown in Fig. 7-56B and 7-56C.   (View)

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HIGH_VOLTAGE_SUPPLY

Published:2009/7/3 2:44:00 Author:May

Circuit NotesA 6 V battery can provide 100-150 Vdc center-tapped at a high internal impedance (not dangerous though it can inflict an unpleasant jolt). A 6.3 V transformer is connected in reverse with a transistor used in a Hartley oscillator configuration. The frequency of operation may be controlled by varying the value of the 10 K ohm resistor. The 10 μF capacitor must have a working voltage of at least 250 Vdc.   (View)

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HIGH_VOLTAGE_GEIGER_COUNTER_SUPPL

Published:2009/7/3 2:39:00 Author:May

Circuit NotesThis circuit will generate about 300 volts dc-at a very low current，but enough for a GMtube．   (View)

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SIMPLE_HIGH_VOLTAGE_SUPPLY

Published:2009/7/3 2:37:00 Author:May

Circuit NotesA light dimmer, a 1 pF capacitor and a 12 V car ignition coil form the simple line powered HV generator. The current in the dimmer is shown in Fig. B. At times t1, t2,..., set by the dimmer switch, the inner triac of the dimmer switches on, and a very high and very fast current pulse charges the capacitor through the primary of the induction coil. Then at a rate of 120 times per second for a 60 Hz line, a very high voltage pulse appears at the secondary of the coil. To obtain an HV dc output, use a voltage doubler. D1 and D2 are selenium rectifiers (TV 18 Siemens or ITT) used for the supply of television sets. High value output shock protection resistors, R, are recommended when suitable.   (View)

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VACUUM_TUBE_AUDIO_AMPLIFIER_POWER_SUPPLY

Published:2009/7/24 4:04:00 Author:Jessie

A suitable power supply that provides isolation from the 120-Vac line is shown. The circuit uses two filament transformers connected back to back. The secondary voltages can be almost any value, as long as they are equal. A 1:1 isolation transformer can be substituted, if available. The transformers should be rated at least 25 VA or more.   (View)

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15_A_positive_adjustable_voltage_regulator_1

Published:2009/7/24 0:03:00 Author:Jessie

The LLM is a three-terminal adjustable regulator IC with an output range from +1.2 to +37V, with the output voltage set by two external resistors. Because the regulator is floating, higher output voltages can be obtained as long as the maximum input-output voltage differential is not exceeded. Characteristics are shown in Fig. 7-59B, 7-59C, and 7-59D.   (View)

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5_A_negative_adjustable_voltage_regulator

Published:2009/7/23 23:57:00 Author:Jessie

The LAS79HG is four-terminal adjustable-regulator IC with an output range from -2.6 to 30 V, providing remote sensing from a single pot. Characteristics are shown in Fig. 7-56B and 7-56C.   (View)

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Basic_F_V_converter_with_cascade_transistor

Published:2009/7/23 23:57:00 Author:Jessie

Fig. 12-22 This circuit is similar to that of Fig. 12-19, but with a cascade transistor at the output to improve nonlinearity to 0.006% (typical). Again, set the 5-kΩ gain adjust for 10-V output with a 10-kHz input. National Semiconductor, Linear Applications Handbook 1991 p 1299.   (View)

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