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參數資料
| 型號： | LM1042 |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 模擬信號調理 |
| 英文描述： | Fluid Level Detector |
| 中文描述： | SPECIALTY ANALOG CIRCUIT, PDIP16 |
| 文件頁數： | 7/8頁 |
| 文件大小： | 170K |
| 代理商： | LM1042 |
Application Notes
(Continued)
TL/H/8709–12
FIGURE 9
PROBE CURRENT REFERENCE CIRCUIT
The circuit defining the probe circuit is given inFigure 10. A
reference voltage is obtained from a bandgap regulator de-
rived current flowing in a diode resistor chain to set up a
voltage 2 volts below the supply. This is applied to an ampli-
fier driving an external PNP transistor to maintain pin 3 at 2V
below supply. The emitter resistance from pin 3 to supply
defines the current which, less the base current, flows in the
probe. Because of the sensitivity of the measurement to
probe current evident in Figure 3 the current should be ad-
justed by means of a variable resistor to the desired value.
This adjustment may also be used to take out probe toler-
ances.
TL/H/8709–13
FIGURE 10
TYPICAL APPLICATIONS CIRCUIT
A typical automotive application circuit is shown inFigure 11
where the probe selection signal is obtained from the oil
pressure switch. At power up (ignition on) the oil pressure
switch is closed and pin 8 is held low by R4 causing a probe
1 (oil level) measurement to be made. Once the engine has
started the oil pressure switch opens and D1 pulls pin 8 high
changing over to the second auxiliary probe input. The ca-
pacitor C
5
holds pin 8 high in the event of a stalled engine
so that a second probe 1 measurement can not occur in
disturbed oil. Non-automotive applications may drive pin 8
directly with a logic signal.
TL/H/8709–14
FIGURE 11. Typical Application Circuit
7
相關PDF資料 |
PDF描述 |
|---|---|
| LM1042N | Fluid Level Detector |
| LM104 | Negative Regulator |
| LM304 | Negative Regulator |
| LM204 | Negative Regulator |
| LM204H | Negative Regulator |
相關代理商/技術參數 |
參數描述 |
|---|---|
| LM104-204-304 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:曾流調整器扣用于很多其他控制虛用 |
| LM1042N | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Fluid Level Detector |
| LM1042N/A+ | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:FLUID DETECTOR|BIPOLAR|DIP|16PIN|PLASTIC |
| LM1042N/B+ | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:FLUID DETECTOR|BIPOLAR|DIP|16PIN|PLASTIC |
| LM1044 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Analog Video Switch |
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