Circuits & Schematics: metal

1. Design an RTD interface with a spreadsheet
   Robert S. Villanucci
   Circuits Analogue Design Measurement Analog Devices AD633 OP177
   .. the output of the sensor. The most popular RTDs are made from platinum with a resistance value of 100 Ω at 0 C and a metal purity that allows them to follow a standard European curve with a positive-temperature coefficient, α, ...
   Feb 25, 2025

2. 1-A, 20-V, PWM-controlled current source
   Stephen Woodward
   Circuits Supply ON Semiconductor LM337
   .. shows the circuit. Figure 1. LM337 mates with a generic hex inverter to make an inexpensive 1-A PWM current source. (* = 1% metal film). I OUT = 1.07(D 0.07), I OUT 0. ACMOS inverters U1b through U1f accept a 10 kHz PWM signal to generate a ...
   Feb 7, 2025

3. Metal detector uses single IC
   Rachel Hageman Steve Hageman
   Circuits Measurement National Semiconductor LM389
   .. 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, ...
   Feb 5, 2025
4. How to collect free energy from atmosphere
   Swagatam Majumdar
   Circuits Bad Prescriptions Supply
   .. the output power is achievable through proper set-up of an antenna. Placing an antenna in a close proximity of a large metal object helps generate additional power. The wire of an antenna should be more than 150 feet long, which has to ...
   Jan 15, 2025
5. PWM power DAC incorporates an LM317
   Stephen Woodward
   Circuits Supply Fairchild LM317
   .. than 11 V are available. 11 V is the maximum consistent with HC4053’s ratings, but up to 20 V is feasible if the metal gate CD4053B is substituted for U1. Don’t forget, however, the requirement that R3 = R1||R2. The supply ...
   Jan 14, 2025
6. Ultrasonic mist maker (DIY)
   T.K. Hareendran
   Circuits Analogue Design Oscillators Texas Instruments NE555P
   .. out the resonance frequency of an “unknown” ultrasonic transducer? A: An ultrasonic transducer is a lump of metal and ceramic that has a particular resonant frequency. To operate the transducer at resonance, it must be driven ...
   Dec 24, 2024
7. 0 V to -10 V, 1.5 A LM337 PWM power DAC
   Stephen Woodward
   Circuits Signal Processing, Filters ON Semiconductor LM337
   .. PWM DACs often do. Figure 1 shows the circuit. Figure 1. LM337 joins forces with 4053 CMOS switch to make a macho PWM DAC. Metal gate CMOS SPDT switches U1a and U1b accept a 10-kHz PWM 5v signal to generate a +1.25 V to 8.75 V ...
   Dec 2, 2024
8. RS-232 meets voltage-to-frequency converter
   Stephen Woodward
   Circuits Measurement Interfaces Texas Instruments CD4053B
   .. Reference 1 ). One difference, other than the 100x lower max frequency, between that older DI and this one is the use of a metal gate CMOS device ( CD4053B ) for U1 instead of a silicon gate (HC4053) U1. That change is made necessary by the ...
   Nov 19, 2024
9. Negative time-constant and PWM program a versatile ADC front end
   Stephen Woodward
   Circuits Analogue Design Measurement Texas Instruments TLV9164
   .. gain settings is a useful and unusual feature. Note that R 1 and C should be precision with low-tempco types like metal film and C0G so that the gain/time relationship will be accurate and stable. The 14.43 µs = 11 kHz ...
   Nov 18, 2024
10. Half & Half piezo drive algorithm tames overshoot and ringing
    Stephen Woodward
    Circuits Automation Analogue Design Texas Instruments CD4066B CD74HC4538 TLV7042
    .. U3a timeout triggers U3b, which turns on U1, outputting the full step amplitude, completing the move. The older metal gate CMOS 4066 is used due to its superior low-leakage R OFF spec’ while the parallel connection of all ...
    Nov 12, 2024

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