Uploaded July 2026 | Updated September 2026, 1 hour ago

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JFET as voltage controlled resistors, amplifiers and constant current sources …
↓↓↓ Complete description, time index and links below ↓↓↓

In the last video we used a J176 P-channel JFET as a high/low side DC switch – at which it sucked – and as an AC signal switch – at which it excelled (link below). Now we’ll explore some more JFET circuits.

First we have a look at the ohmic of the characteristic curve. Then we build a voltage controlled resistor and an amplifier. After that we have a look at the saturation region. Towards the end we build two different constant current sources.

00:00 Intro – even more JFET circuits
00:55 Ohmic region – characteristic curve
04:58 Voltage controlled resistor – attenuating
12:37 Amplifier – high impedance inputs
20:39 Saturation region – characteristic curve
23:22 Constant current sources – the simplest
29:57 Wrap-up – that’s it for today, bye

Tutorials: youtube.com/playlist?list=PLwq-2MnM58FKn3920rc1V0qoTsQDheTIw
JFETs – The Dirty Details (1/3): Theory youtu.be/8ETFtddyfoE
JFETs – The Dirty Details (2/3): Practice 1 youtu.be/BtKWRsjCgDE

#jfet #tutorials #tutorial #robertssmorgasbord