Norman Lathrop Enterprises | Norman Lathrop Enterprises
Index To How To Do It Information
Lathrop Report On Newspaper Indexes
A profile of Norman Lathrop Enterprises
Last Updated
  Index Home  |   A-Z Subject Heading Guide    |   Keyword Search  |   Union List 

Detailed entries for one subject from the INDEX TO HOW TO DO IT INFORMATION.
Click on a see also (sa) or tracing (xx) to view detailed entries about a related subject.
The entries are in alphabetical order by magazine name and then in chronological sequence.
To obtain a copy of any magazine article contact your local public library or the publisher.


Telephone line monitor circuit lets a group listen to both sides of a telephone conversation over a small loudspeaker.
AUDIO AMATEUR 1/1994 [Mar 1994] (v.25#1) pg. 39

Telephone amplifier for the incoming voice lets several people listen to a telephone conversation (although they'll still have to take turns talking using the handset). Est. cost: $12 (kit).

Phone amplifier boosts conversations to room volume. Est. cost: $1.
ELECTRONICS ILLUSTRATED Sep 1965 (v.8#5) pg. 80

Integrated circuit which delivers 250 mW to an 8-ohm speaker can be used as a headphone driver, low-power audio amplifier, and telephone pickup amplifier.
ELECTRONICS WORLD Feb 1968 (v.79#2) pg. 74

Telephone broadcaster. Group listening to telephone conversations is possible thru a short-range broadcast band oscillator, a portable radio, and an induction coil pickup under the telephone. Maximum range of 100 ft. Est. cost: $8.
ELEMENTARY ELECTRONICS Jan-Feb 1967 (v.3#3) pg. 55

Speaker-Fone. Can serve as a loudspeaking telephone receiver or a switchless intercom. Est. cost: $25.
ELEMENTARY ELECTRONICS Jul-Aug 1969 (v.8#3) pg. 39

Telephone amplifier use an inductive pick-up.
HANDS-ON ELECTRONICS Jun 1987 (v.4#6) pg. 96

Telephone amplifier circuit uses an inductive pickup.
HANDS-ON ELECTRONICS Aug 1987 (v.4#8) pg. 94

Add a speakerphone to your telephone. Part 1. Project gives talk/listen hands-free telephone communications with upgrade capability for dial-out operation.
MODERN ELECTRONICS [2] May 1986 (v.3#5) pg. 36

Add a speakerphone to your telephone. Part 2. Add an electronic ringer and touch-tone dialer to the speakerphone or any other telephone.
MODERN ELECTRONICS [2] Jun 1986 (v.3#6) pg. 64

Telephone amplifier circuit allows everyone in the room to listen in on a conversation. It can be switched off for privacy.
POPULAR ELECTRONICS [2] Jan 1991 (v.8#1) pg. 81

Fun with op-amps. Part 2. (1) Operation and theory. (2) Telephone amplifier circuit for hearing impaired or noisy environment. (3) Audio alarm sounds a buzzer when the noise level gets too high.
POPULAR ELECTRONICS [2] Feb 1992 (v.9#2) pg. 68

Telephone amplifier feeds conversation to speakers or recording devices.
POPULAR MECHANICS Jan 1969 (v.131#1) pg. 144

Telephone amplifier plugs into phone jack, thus allowing several people to listen to a phone conversation.
POPULAR MECHANICS Feb 1974 (v.141#2) pg. 132

Build an amplifier for your telephone handset. Plug the handset into this accessory and you can talk and listen from anywhere in the room.
RADIO-ELECTRONICS May 1977 (v.48#5) pg. 60

Speaker mate. Turns any regular telephone into a high-quality speakerphone. Est. cost: $50 (kit).
RADIO-ELECTRONICS Jan 1992 (v.63#1) pg. 43

Transistor telephone amplifier lets two listen.
SCIENCE & MECHANICS #214 Feb 1963 (v.34#2) pg. 100