Important: the first transistor is a BD 139 (not indicated in the schematic).

Schematic & demo of a (typical) voltage amplifier. It works on 40 Volt (stabilized and hum free).

With 0,2 Volt AC in it gives approx. 8-10 Volt AC out, sine wave or square wave between 100 Hz and 600 KHz..

At 1 MHz the square wave is not a square but a kind of triangle wave. Anyway: I think it is a useful amplifier for e.g. measuring purposes where a more or less “high” AC Voltage is needed, like showed in my earlier video: “primitive capacitance measurement/the magnitude of capacitance”.

For that test circuit you need approximately 10 V AC out to “push” enough AC current through the capacitor, especially the small value ones.
Link is [ Ссылка ]

SECOND AC square/sine voltage amplifier video (but: max 10 KHz!) is here: [ Ссылка ]




All the videos hat I have published on You Tube can be found via my Channel Trailer: Link is
[ Ссылка ]
In thematic order you can find these video’s under the “comments” section.
Important: to find all the links to the (+/-700) video’s on my YT Channel, select, in the comments section, “NEWEST FIRST”
My books about electronics are available via the website from “Lulu”, search for author “Ko Tilman” there.
[ Ссылка ]=
There is an important video via which you can buy a document where I give links to many of my video’s, published between 2010 and 2018.
Link is: [ Ссылка ]
My books are also available via Barnes and Noble and via Amazon.
Regarding all my video’s: I constantly keep them actual, so the original video’s with the most recent information are always on YouTube. That is the source, and search there. When my video’s are reproduced or re-edited on other websites/channels you can not (!) be sure about the original content (=really working electronics) and important adaptations to the circuits.
Be aware of that, I saw on the internet many of my circuits reproduced in a poor or even not proper way. I can not help that, sorry. Upload 25 november 2018.

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