Homemade Transistor from Cadmium Sulfide Photocell (2009)
3 days ago
- #DIY Electronics
- #Homemade Transistor
- #Field-Effect Transistor
- A homemade FET was successfully created using a cadmium sulfide photocell with an insulated gate improvised from scotch tape and water.
- The experiment required darkness to avoid light saturation, and slight light could improve performance; the device showed transistor action with power gain but low voltage gain.
- Gate voltage swings of 75-175 VDC (reversible polarity) controlled photocell current, with high gate impedance leading to high power gain despite minimal gate current.
- The device acted as an enhancement-depletion FET: positive gate voltage increased current, negative decreased it, with dynamic response and inverted sawtooth waveform output.
- A functional amplifier circuit using the homemade transistor amplified 60 Hz body buzz, demonstrating practical power gain, though voltage gain was low (~1/10).