Reverse voltage
The blocking voltage (also the threshold voltage is referred to) those electrical voltage , which on a reverse-biased pn junction is applied. The usually very low reverse current then flows through the semiconductor junction .
From a certain characteristic voltage U z ( breakdown voltage ) leads to breakthrough . In the case of a pn junction, this means a steep rise in the current far above the saturation value I S at a critical reverse voltage. The cause of the breakthrough are very high electric field strengths . Three different mechanisms can be described:
- Impact ionization with avalanche or avalanche breakthrough , e.g. B. IMPATT diode for generating high frequencies, avalanche photodiodes (avalanche photodiodes) or avalanche protection mechanism in MOSFET and rectifier diodes, overvoltage protection with transient suppressor or suppressor diodes , Z diodes from about 5 volts
- Zener breakthrough ; Principle of the Zener diodes up to about 5 volts, to provide reference voltages
- Thermal breakdown ; Breakdown of the reverse voltage due to high temperature, usually destruction of the diode by diffusion processes
Individual evidence
- ^ "IEC-60050 Electropedia" Electropedia of the International Electrotechnical Commission. Retrieved October 16, 2012.