I found this interesting circuit in a 1958 documentation. It is a wired intercom that can be used in offices or at home, or even in demonstrations.
The circuit does not use power transformers, so in addition to the tubes we have three critical components for those who may wish to attempt assembly.
The first two are transformers that can be common transformers for output of valves with an impedance of 2 to 5 k ohms. The third is the RF shock that can be replaced by the primary winding of a small 6 to 12 V transformer with 300 to 500 mA.
The loudspeakers are ordinary 10 cm and the wires can be up to 30 meters long. The talk-to-listen key is in the transmitting station.
In figure 1 the complete diagram of this interesting intercom.
Figure 1 - Tube intercom - complete circuit. | Haga click en la imagen para ampliar |
