Can someone show me in the most generic form how a clamping diode works? I have some cicuit anaylsis background from years ago, but I cant seem to remember coming across this item. I've read the theory but I still don't see it in a real circuit and how it "clamps". Are there different ratings on clamping diodes? Basically I have a problem with a transient spike that jumps from nominal 20V dc up to 30V dc and down to
-10V dc in about 1ms time. I'm was told a clamping diode will work.
Thanks
There are two distinct ways to clamp voltage peaks with diodes. one involves a diode from the signal line to a supply voltage or ground that becomes forward biased when the signal voltage gets one diode drop (about .3 volts for silicon Schottky diodes and about .6 volts for silicon junction diodes) past the particular supply voltage. This provides a low impedance path for current that tends to load the signal voltage down if it tries to go further.
The second method involved putting a device between the signal and ground that has a high impedance up to some breakdown voltage, and switches to a low impedance for higher voltages. A zener diode is the classic example of this sort of clamp but there are lots of variations, including Metal Oxide Varistors for higher voltages and bidirectional high surge current zeners. These devices turn the energy that would have produced an over voltage into heat.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.