Search Results
Intercom
If you compare this intercom to modern FM and wireless designs, you will certainly sau it outoded. The intercom circuit fulfills its tasks - to provide a reliable communication line and is very simple to construct. The circuit is made up of an amplifier, two switches and two loudspeakers. If additional stations (speakers) are wished, [...]
FM transmitter with SMD
Let’s construct a low-power FM transmitter using surface-mount devices (SMD) that will be received with a standard FM radio. Soldering surface mounted devices is not so hard and actually is quite easy. There are many designs for small FM transmitters but they have some problems. First, you need an audio amplifier to get enough modulation. [...]
Dynamic mic preamplifier
This mic preamp uses the low noise IC uA739. The circuit is an example of how a good preamplifier can be designed for dynamic microphones. The IC houses two identical integrated preamp circuits. The second preamp is used in identical manner for the second channel of the stereo microphone.
Diagram bellow shows the pin numbers (in [...]
