Electronics Project Repository 

Distributed under the CERN Open Hardware License (https://ohwr.org/cern_ohl_p_v2.txt)

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• 1. Crystal radio

     Sound clip1, clip2, clip3

     Contributors: Chirag Kalelkar, Chandranibh Brahma (ME), Yash Foujdar (ME)

• 2. Dual-polarity regulated power supply (+/-12V) [Ver. 1]

     Contributors: Chirag Kalelkar, Yash Foujdar (ME)

• 3. Dual-polarity regulated power supply (+/-12V) [Ver. 2]

     Contributor: Chirag Kalelkar

• 4. Gas alarm

      Movie

      Contributors: Chirag Kalelkar, Yash Foujdar (ME)

• 5. Lorenz model

     Movie

     Contributor: Chirag Kalelkar

• 6. Portable white noise source

        Contributor: Chirag Kalelkar

• 7. Pocket AM radio

     Sound clip1, clip2, clip3

        Contributor: Chirag Kalelkar

• 8. LED candle 

        Movie

                             Contributor: Chirag Kalelkar

• 9. Tesla coil (Slayer Exciter circuit)

        Movie

        Contributors: Tankala Susritha (EE), Chirag Kalelkar

• 10. Metal detector

          Cellphone, Aluminum-sheet, Wooden-disk, Screwdriver-along-coil-axis

          Contributors: Grandhi Satya Sai (EE), Chirag Kalelkar

• 11. Useless machine (simplest possible design)

          Movie

          Contributors: Tusharanshu Pandey (ECE), Chirag Kalelkar

• 12. Human proximity/Metal detector 

          Hand, Aluminum-sheet, Paper

            Contributor: Chirag Kalelkar

• 13. (a) Speaker amplifier module with volume and gain control

            Movie

                    (b) Microphone pre-amplifier module with gain control

               Movie        

            Contributor: Chirag Kalelkar

• 14. White noise source (for regulated power supply) [redundant]

• 15. Dual-polarity regulated power supply (variable,portable) [Ver. 3] 

        Movie

            Contributors: Tusharanshu Pandey (ECE), Chirag Kalelkar, Rickarya Das (EE)

• 16. "Pseudo-AM" radio transmitter (portable)

            Contributors: Chirag Kalelkar, Harshith Reddy (EE)

• 17. Lock-in amplifier

            Contributors: Viraj Bhosale (ECE), Chirag Kalelkar

• 18. Diode tester (portable)

Movie

            Contributors: Sanjay R (ECE), Chirag Kalelkar

• 19. Oscilloscope art

Cat, Butterfly, Heart, Thumbs-up, Text

            Contributors: V D N Eswar Tati (ECE), Chirag Kalelkar

• 20. Instrumentation amplifier

            Contributors: V D N Eswar Tati (ECE), N V Hardhik (ECE), Chirag Kalelkar

• 21. PID (Proportional-Integral-Derivative) controller

            Contributors: K Rupya Lakshmi Sai Sri (ECE), Chirag Kalelkar

• 22. Audio transmission via infrared

            Contributors: Harshith Reddy (EE), Chirag Kalelkar

• 23. Voltage-Controlled Oscillator

            Contributors: Sulagna Basack (ECE), Sagnik Mondal (ECE), Chirag Kalelkar

• 24. Window comparator module

Contributors: Viraj Bhosale (ECE), Chirag Kalelkar

• 25. Frequency-to-voltage converter 

Contributor: Chirag Kalelkar

• 26. Phase detector (switching circuit)

Contributors: Sinchan Dutta (ECE), Chirag Kalelkar

• 27. Automatic Gain Control

Contributors: Tannistha Das (ECE), Chirag Kalelkar

• 28. State-variable filter (KHN)

Contributors: Anirudh Rao (ECE), Chirag Kalelkar

• 29. Coloured noise generator (white,pink)

Contributors: Viraj Bhosale (ECE), Chirag Kalelkar

• 30. Curve tracer (2-pin,passive components) 

Contributors: Chirag Kalelkar, Viraj Bhosale (ECE)

• 31. Single-transistor chaotic (Colpitts) oscillator

Period-doubling bifurcation, Chaotic art

Contributor: Chirag Kalelkar

• 32. Switched-capacitor filter 

Contributors: Viraj Bhosale (ECE), Pydipati Suhitha Reddy (ECE), Prateek DR (ECE), Chirag Kalelkar

• 33. Sound modulation using diode ring mixer

     song, song(modulated), music, music(modulated), speech, speech(modulated)

Contributors: Venkata Mukund (EE), Chirag Kalelkar

• 34. Stochastic resonance

Contributors: Viraj Bhosale (ECE), Chirag Kalelkar

• 35. AM radio transmitter

Contributor: Pydipati Suhitha Reddy (ECE), Chirag Kalelkar

• 36. Minimalist relaxation oscillators

   Relay oscillator

Contributor: Chirag Kalelkar

• 37. Gyrator as a variable capacitor

Contributors: Sarvan Tallam (EE), Chirag Kalelkar

• 38. True power meter

Contributors: Chirag Kalelkar, Pydipati Suhitha Reddy (ECE)

• 39. Constant-current electronic load 

Contributor: Chirag Kalelkar

• 40. Log/Antilog amplifier

Contributor: Chirag Kalelkar

• 41. Joule Thief circuit

Contributor: Chirag Kalelkar

• 42. Non-contact AC voltage detector [ongoing]

Contributor: Chirag Kalelkar

• 43. Switched-Mode Power Supply (portable)

Contributors: Arnav Pandey (EE), Chirag Kalelkar

• 44. THD meter/Tunable notch filter [ongoing]

Contributor: Chirag Kalelkar, Sanjay Thodupunuri (ECE)

• 45. Class-D amplifier [ongoing]

Contributor: Sarvan Tallam (EE), Chirag Kalelkar

• 46. Rogowski coil (AC current sensor) [ongoing]

Contributor: Arnav Pandey (EE), Chirag Kalelkar

• 47. High-resistance meter [ongoing]

Contributor: Chirag Kalelkar

Last update: 3/11/26