Circuits & Schematics National Semiconductor

1. Metal detector uses single IC
   Rachel Hageman Steve Hageman
   Circuits Measurement National Semiconductor LM389
   The original application of the circuit in Figure 1 was to locate coins, but it applies wherever you need to locate metal objects. The circuit uses a beat-frequency technique: Whenever a metal object comes close to the search coil, the metal causes ...
   Feb 5, 2025
2. An ultra low distortion oscillator with THD below -140 dB
   Vojtech Janásek
   Circuits Oscillators Measurement National Semiconductor LME49710
   ADC circuits that resolve signal into 20 or more bits need a low-noise signal source for measuring parameters such as harmonic distortion or effective number of bits. A notch filter removes the fundamental frequency from the oscillators signal for ...
   Jan 10, 2025

3. Voltage reference improves JFET
   Clayton Grantham
   Circuits Analogue Design Supply National Semiconductor LM4130
   The common JFET current-source in Figure 1a has average output impedance and depends heavily on the JFET's V P and I DSS variations. These manufacturing variations limit the initial accuracy of the current setpoint that the circuit can obtain ...
   Jul 22, 2021
4. Current source has high output impedance
   Clayton Grantham
   Circuits Analogue Design Supply National Semiconductor LM4130
   A reference current source needs high accuracy, low temperature drift, and high output impedance. Available IC current sources come with some of these features. However, at current levels greater than 1 mA, their output impedance decreases to less ...
   Jun 10, 2019
5. Simple circuit times bathroom fan
   Circuits Automation National Semiconductor LM2905
   Maxwell Strange EDN Forget to turn off the ceiling fan in your bathroom? Install the simple timer in Figure 1. It's located out-of-sight in the fan unit, and you turn it on via the wall switch. The circuit costs virtually nothing, using junk ...
   Jul 4, 2018
6. Comparing the NE555 Timer and LM386 Amplifier as Inductorless DC-DC Converters
   Petre Petrov
   Circuits Supply Power National Semiconductor NE555 LM386
   Choosing between two widely available, multisourced ICs for the core of an inductorless dc-dc converter the NE555 timer and the LM386 audio amplifier requires a look at their key specifications and performance in typical circuits. The bipolar NE555 ...
   Apr 6, 2016
7. Precision full-wave signal rectifier needs no diodes
   Circuits Analogue Design National Semiconductor LMC6482
   Jose Blanes EDN Rectifier circuits based on semiconductor diodes typically handle voltage levels that greatly exceed the diodes' forward-voltage drops, which generally don't affect the accuracy of the rectification process. However, the rectified ...
   Sep 30, 2015
8. Switch Mode Power Supply +5V
   Circuits Supply Power National Semiconductor LM2671 LM2674
   This Switch Mode Power Supply circuit use the IC from National Semiconductor has been producing and designing ICs for use in switch-mode power supplies for many years. The application of these devices is normally straightforward, helped by the ...
   Jan 6, 2011
9. 20 W Audio Amplifier
   Rajkumar Sharma
   Circuits Audio Beginners National Semiconductor LM1875
   This schematic is designed to operate with minimum of external components. This amplifier offers high quality performance at very low distortion. Project is based on National LM1875 IC. The IC is thermal and short circuit protected. Specifications ...
   Feb 25, 2010
10. Mint Tin Bike Light
    Circuits Light National Semiconductor LM3410
    This year I’ve been going on a lot of bike rides with friends, sometimes on public roadways, sometimes after dark. My bike has a nine watt 500 some odd lumen headlight, which makes it easy to see where I’m going, and definitely makes me ...
    Nov 23, 2009

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