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Barrier voltage of diodes Silicium/Germanium: how to measure it and why it is important



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Video about the barrier voltage of diodes (Silicium and Germanium) and why this is important. Everything is told in the video, so no more remarks here. To get a precise barrier voltage in some electronic applications you can switch Silicon and Germanium diodes in series. Or, at first, do precise measurements of certain silicon diodes and switch them in series. Say diode A = 0.47 V and diode B = 0.77 V, in series they are 0.47 V + 0.77 V = 0.91 Volt. But you can also use a voltage divider/potentiometer parallel to that bunch of series diodes to align everything to 1/10 of a volt.

The diode that I wanted to show (but had to skip on some moment in the video, at 8.51 in the video) was the RL439 (from a computer board of the 1970's) made by Siemens Germany. Tested it afterwards: on 10 K I measured (3 of them): 0,46 V and 0,51 V and 0,49 V. On 2K5 (2500 Ohm) I measured: 1.2 volt and 1.00 volt and 1.06 volt.

All diodes suffer of temperature effects, by the way, for absolute stability they must be put into an “oven” that gives them a precise and constant temperature.

On the other hand: for precision voltage applications we nowadays have a big bunch of temperature compensated Chips that can do such a job perfectly.

And you can “forward voltage” a Germanium or Silicon (detection) diode, by giving it a tiny (+) voltage on its anode, this can help in e.g. radio detection of AM signals or otherwise (more in other radio video’s on my YT channel).

There are more than 1200 Video’s on my YT channel. I only do analog electronics: audio amplifiers, analog measuring devices, radio circuits, many Shortwave radios, many oscillators HF and audio, other audio & shortwave circuits. Also many (test) generators for all kinds of waveforms, both in the audio range and HF. Also simple “switch” circuits like the Schmitt triggers acting on different input voltages, 555 circuits and circuits of basic electronics issues like “Ohms law”, resistance properties, capacitance properties, the capacitors testing process, electronic “matching” in audio circuits and audio amplifiers, audio pre amplifiers, microphone amplifiers, etc. In all cases you find the schematic inserted in the video.

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I keep all my YT videos constant actual, so the original video’s with the most recent information are always on YouTube. Search there, and avoid my circuits that are republished, re-arranged, re-edited on other websites, giving not probable re-wiring, etc. Some persons try to find gold via my circuits. I take distance from all these fake claims. I cannot help that these things happen. Upload 5 november 2021.
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