Simple Tone Oscillator Generator by 2N2222 This is Simple Tone Oscillator Generator. It is use transistor 2N2222 and 2N2907 be main part. By control tone sound with R2 – 50K and use 8ohm ….
Tone Generator by 2N4891 This be Basic Tone Generator by UJT Transistor 2N4891 numbers. By it s can give with small-sized loudspeaker s have a voice electric loud bell moderately….
Tone Burst Generator by LM555 Friends take an interest try build Tone Burst Generator be simple is. Try this circuit like sure because use IC 7555 , highly popular again. Assure that not sure difficult press the the secretariat of the…
Stereo Test Tone Generator with LM324 and LM1458 The purpose of this circuit is to create a pair of sine waves for testing stereo equipment. While it is useful for many types of audio test tone generation, the circuit is specialized for the purpose….

Phone “Hold” With Music This circuit will allow you to place a phone call on hold and if you wish to have them listen to music while they are on hold. The circuit operates as follows: The RED wire from the phone jack is typically positive and the GREEN wire is negative or ground….

Telephone Amplifier by LF351+TBA820M If phone your light exceedingly ring. Invite come to this way. I thinks this circuit can help. It is Telephone Amplifier circuit. By have pillar equipment be IC LF351 perform enlarge telephone signal from pick up give the power goes up…

Protection For Telephone Line A long time ago when telephones were so simple almost nothing could go amiss from an electrical point of view, Telecom operators installed surge protection on all telephone lines exposed to storm risks. Paradoxically,…