This circuit is a utility circuit. The base circuit is a 3 way video splitter by Hervé Cadinot, which uses TEA5114, a RGB switcher/amplifier. The point of using this integrated circuit in this application is that there is an amp for each R,G, and B channel, so it’s possible to use it to amplify 3 composite video signal, the goal is to be able to distribute the source signal to 3 different monitors without loss.
PCBs and kits are available at the shop.
Here is the base circuit:
R1 adapt the impedance from the source, C1 to C3 are coupling capacitors, which will remove any DC offset from the signal. The 3 amps in the TEA5114 amplifies the source signal and R2 to R4 + TEA5114 outputs impedance gives around 75ohm at the output.
The power supply is composed of 2 diodes that make the voltage drop from 12V to 10V, C5 is a filtering cap and C4 is a decoupling cap for the TEA5114.
Bill of material:
|Ref designator||Value||Part number|
|R1||75R||Any 5% 1/4W resistor|
|R2||68R||Any 5% 1/4W resistor|
|R3||68R||Any 5% 1/4W resistor|
|R4||68R||Any 5% 1/4W resistor|
|C1||100nF (film)||or any ceramic capacitor|
|C2||100nF (film)||or any ceramic capacitor|
|C3||100nF (film)||or any ceramic capacitor|
|C4||100nF (ceramic)||Decoupling cap, has to be ceramic|
|C5||10uF (electrolytic) 16V or more|
|D1||1N4001||any 1N400X diode|
|D2||1N4001||any 1N400X diode|
|U1||TEA5114||obsolete (included with PCB and kit)|
|DC connector||Tayda DC Power Jack 2.1mm Barrel-Type PCB Mount or Kobiconn 163-7620E-E|
|IN||RCA socket||CUI RCJ-024 or Keystone 586|
|OUT A||RCA socket||CUI RCJ-024 or Keystone 586|
|OUT B||RCA socket||CUI RCJ-024 or Keystone 586|
|OUT C||RCA socket||CUI RCJ-024 or Keystone 586|
Assembly is quite straight forward:
– Place and solder the 4 resistors, then the 2 diodes, then the 5 capacitors and finally the power connector.
– Plug a 12VDC PSU and check that you have 10V at D2 cathode.
– If that’s the case, place and solder the TEA5114 and the 4 RCA connectors.
When a 75 ohm load is applied to each outputs (= each output is plugged to a device), current consumption is around 90mA. So best is to use a 12VDC/center positive/200mA PSU at least.