Telephone circuit diagrams

• Alarms and security
• Arduino
• Audio
  • Amplifiers
  • Audio level meter
  • Intercom
  • Mixer
  • Mixers
  • Preamplifiers
  • Tone control
• Automotive
• Digital
• For home
• Fun and games
• General electronics
• Infrared (IR)
• LED & Light
  • LED
  • Light and music
  • Misc
• NENAD
• PC related
• Power
  • AC to DC
  • Battery charger
  • DC to DC
  • High voltage
  • Inverters
  • Misc power
  • Solar power
  • Voltage stabilizers
• PWM and power control
• Radio
  • AM receiver
  • AM transmitter
  • Amplifier
  • Field strength meters
  • FM receiver
  • FM transmitter
  • Misc
  • TV transmitters
• Sensor and control
  • IR sensor
  • Light sensor
  • Metal detector
  • Moisture sensor
  • Other sensor
  • Sound sensor
  • Switches and relays
  • Temperature sensor
• Sound generator and oscilator
  • Metronome
  • Oscilator
  • Sound generator
• Telephone
• Timer
• Tools and measuring
  • Quartz oscillator tester
• Video