
STEP 5. NOISE IMMUNITY CONTINUED
HOW DOES NOISE GET INTO ELECTRONICS?
Energy Coupling
(Conductive, Inductive, Capacitive)
• EMI - Current surges
(ElectroMagnetic Interference) An electrical disturbance in a
system due to natural phenomena, low-frequency waves
from electromechanical devices or high-frequency
waves (RFI) from chips and other electronic devices.
Allowable limits are governed by the FCC.
• RFI – high impedance devices requiring very
limited current.
(Radio Frequency Interference) High-frequency electromagnetic waves that
emanate from electronic devices such as chips.
If the source is sufficiently strong this can enter your circuit.
47
STEP 5. NOISE IMMUNITY
design solutions
Protect from?
• ESD
• Solution: Proper grounding, optical isolators,
capacitors
• Transients
• Solution: Low pass filter, optical isolators,
software sampling
• Reverse polarity
• Solution: Diode circuits to protect against,
fuse.
48
Kommentare zu diesen Handbüchern