Home

Automatic telephone recorder device circuit

This circuit can hook with the telephone, hang up automatically synchronize start and stop the tape recorder and record the conversation. Tape recorder used here as a voice microphone input jack input, easy to use. Here's how it works.

Telephone lines and X, Y both ends of the connection. R1, R2 voltage divider formed, R2 of the voltage (A, B) is sent to the tape recorder's microphone input. Because different tape recorder microphone input impedance of the differences in use may need to effect appropriate adjustments based on actual recordings of this resistor. The role of capacitor C1 is isolated DC voltage on the telephone line. D1 ~ D4 constitute a polarity conversion circuit, so no need to consider the use of telephone lines in the polar and get guaranteed T1 positive polarity voltage. We know that the voltage on the telephone line when the hook is generally not about 50V, after picking down to 10V or so. Without hook, 50V line voltage of about 12V regulator to turn D5 breakdown, by R3, R4 constitute a voltage divider circuit, saturated conduction time T1, T2 end, J1 off, the tape recorder does not work. When the phone off-hook, call the voltage down to 10V or so. As time D5, R4 approximate the voltage 0V, cut-off point T1, T2 turn, J1 is closed, the tape recorder is energized to work to complete the auto-sync recording. Capacitor C2 is to prevent the lines from the interference (eg when using pulse dial phones) or frequent jitter J1 leaving pull the set. Also before using the device, need to press the tape recorder of the recording key.

Free Electronic ProjectsElectronic hobby projects, Electronic circuit, Circuits, Hobby circuits, Digital circuits, digital e...Digital clock circuitOne , designed to 1 . familiar with the IC 's pin arrangement . 2 . to acquire all the chip logic fu...IPM drive and protection circuitp> Abstract: This paper introduces the basic operating characteristics of the IPM and the IPM...Power supply switching protection circuitAbstract: In order to switch to emergency power failure in the harsh environment and safe conditions...LM567 Universal tone decoder integrated circuit applications567 for the general tone decoder, when the input signal in the pass band to provide saturated transi...Inverter circuit board and maintenanceA common style car on the market the main indicators of inverter products Input voltage: DC 10V ~...Automatic hand washer and automatic hand dryer circuitAfter SARS, more and more people on the daily lives of more attention to health habits, the daily nu...Automatic telephone answering device circuitAutomatic telephone answering device circuitry as shown. IC2 figure of 10 seconds voice recording ci...Automatic Telephone call recording circuit This circuit is used to record the calls automatically. A idle tape recor...Quick Introduction to Voice Trilogy Integrated CircuitsBasics Young enthusiasts started his electronic technology, we might start with the most innovati...DC motor control circuit-4Commutator permanent magnet DC motor, is a very broad application. Just add the appropriate voltage ...Long-range cordless telephone and ordinary telephone connection method circuitIn many remote villages, the erection of telephone lines is too difficult, so more use of long-dista...Pressure boiler circuit with automatic temperature control deviceSmall pressure boiler heating hot water circulation is by pumps to force circulation . When the boil...Telephone communication circuits-2// Telephone circuit (1) Telephone circuit (2) Telephone circuit (3) Telephone circ...Telephone communication circuits-3// Telephone circuit (22) Telephone circuit (23) Telephone circuit (24) Telephone c...Remote controlled Telephone pickup circuit for mulfi functionsathe remote control function to the office workers bring a lot of work and life easy . I have a func...Three in one circuit Integral A - D converter consisting of single ICL7149 3 1 -2 digital multimeter circuit automatic Range convertoir circuitAutomatic telephone recording device control circuitAutomatic telephone message circuitThe devices use the existing home tape recorders, call recording can be both, at home, no one can au...Optocoupler drive circuitFirst, the circuit using optocoupler Why? Electrical isolation requirements. Between A and B circ...

Free Electronic projects & 8085 projects

Recent Projects

Automatic telephone recorder device circuit