More about phone (291)

1-07-1979 | Before going on to describe the circuit of the receiver, there is one point worth noting. Although primarily intended for use in an ultrason...

1-11-1978 | Modern technology has produced fast transport and centralised industry. A somewhat less desirable side-effect is that close relations have t...

1-07-1978 | This microphone preamplifier incorporates automatic gain control, which keeps the output level fairly constant over a wide range of input...

1-07-1978 | Stereo headphones are usually connected to the loudspeaker outputs of the power amp via an attenuator. Although this represents the cheapes...

1-12-1977 | This compact, low-noise, battery- powered preamplifier can be used to boost the signal from electret and low impedance dynamic micropho...

1-07-1977 | This preamp is specifically intended for use with low impedance microphones; its advantages are high output level, large ban...

1-07-1977 | This circuit is designed to indicate· whether anyone has attempted to telephone the householder during his absence. If the te...

1-07-1976 | The disadvantage of normal headphones is that they are connected to the main hifi equipment via a length of cable. This is unsightly,...

1-07-1976 | It is almost always impossible for a motor cyclist and his passenger to maintain aural contact without dangerous acrobatics. The cir- cu...

1-07-1976 | This amplifier is intended to be used in conjunction with the popular Sennheiser stereo headphones (HD 414, HD 424). These headphones...