Category: Builds
-
Testing v8.1 of the BJT Transistor Experimentation Board…
…with a Colpitts oscillator setup. – See the schematics in the images. Version 8.1 adds: * Optional Vcc+ supply filter using resistor, ferrite bead or inductor * Collector resistor split for gain boost experiments * Additional feedback network for common collector stages * Extra ground point for cleaner external feedback wiring Everything worked as expected.…
-
The Symmetric Wilson Current Mirror – Free KiCad PCB Design Files
Get the free Kicad PCB design files of the Symmetric Wilson Current Mirror – And start build your own for your DIY audio projects. Get the Kicad files from Github, and order where you want : (Both versions available. Future updates too.) https://github.com/ufelectronics/Symmetric_Wilson_Current_Mirror – Or order directly from PCBWay : (Plain version, without…
-
Uneven DIY coils for RF are a past
Winding them with bare copper wire: * They won’t get an even distributed spacing * Handling them, changes their inductance * They partly uncoil again, as you let go Nothing is controllable. Until you take duct tape, alias ‘Panzer-tape’, alias Gaffa and what else you call it. Take a random object with the desired diameter.…
-
Free KiCad schematic for a BJT based LC Colpitts Oscillator, 5 – 8 MHz
This oscillator is based on two transistors. No crystals, by purpose. It can oscillate on various frequencies between 4.8 MHz and 8 MHz. With a variable capacitor (around 15 – 400 pF) instead of C2, you can dynamically vary the frequency in parts of that range. Its functionlity is verified by real world build and…
-
16 pF to 650 pF DIY variable capacitor
16 pF to 650 pF DIY variable capacitor from ordinary aluminium foil (alufoil), A4 paper and a cardboard tube from an empty alufoil package. Roll one round of alufoil on the blank cardboard tube. Fix it with tape. Leave 5 cm / 2 inch free from alufoil at one end. Roll a A4 paper around,…
-
DIY Single to Dual Power Supply from 5V – 15V, with Virtual Ground
DIY Single Rail to Double Rail with Virtual Ground / Rail Splitter / Voltage Divider Just released a video on how to create a small dual power supply based on a single power supply of between 5V an 15V. Schematic update 2028.03.03. NOTE: The pinout in the schematic does NOT represent the μA741C pinout. The…