on/off Switch

[daisycutter]

Hello,

I have a Videosignal and an Signal from D-Flip-Flop. If the Signal from the D-Flip-Flop is about 5V, the Videosignal switch off, otherwise it should switch on. I first tried a circuit with an jfet (B245A). The Videosignal should pass the Transistor from Drain to Source. If the Gate has 5 V, the Transistor should switch the signal off .
Do anyone has an idea, what to do ?

daisycutter

 

[williB]

Hello,

I have a Videosignal and an Signal from D-Flip-Flop. If the Signal from the D-Flip-Flop is about 5V, the Videosignal switch off, otherwise it should switch on. I first tried a circuit with an jfet (B245A). The Videosignal should pass the Transistor from Drain to Source. If the Gate has 5 V, the Transistor should switch the signal off .
Do anyone has an idea, what to do ?

daisycutter

that didnt work??
it should have..unless your jFET was hooked up inproperly..
how did you hook it up ?
the FET acts as a nice low resistance switch .

 

[Sebi]

Use a video signal switch IC, it have proper 75ohm in and out impedance. TEA2014 or similar.