Electrostatic deflexion?

[Telecolor 3007]

Is true that is the early days of electronic television, tv sets had electrostatic deflexion - the deflexion was made with a magnet, not with a coil?

[KB9KXH]

Oscilloscopes use four plates to control the beam.

[Telecolor 3007]

But tv sets?

[Adam]

Lots of older TVs use electrostatic deflection (4 plates inside the picture tube to control the beam), all these old motorolas I keep picking up are like this, here's a schematic. The 7JP4 is the electrostatic picture tube used in the Motorola, any TV that says it has one of these is electrostatic. The electrostatic crt below is the 7GP4.

The voltage is varied across the plates inside the tube and this is what deflects the beam, (there are no permanent magnets involved) Now some early electromagnetic sets use a magnet around the neck of the tube behind the yoke for focusing, my Hoffman 610 uses one of these, and some sets also used an electromagnet instead, the Admiral 20A1 uses one. Here is a picture of the Hoffman showing the magnet. The Hoffman uses the 10BP4 one of the most common tubes in early electromagnetic sets.

[John Folsom]

" Is true that is the early days of electronic television, tv sets had electrostatic deflexion - the deflexion was made with a magnet, not with a coil?"

You are confusing your terms. Electrostatic defeection uses electric fields (created by voltagedifference on deflection plates) to bend the electron beam. Magnetic defeection uses a coil of wire to produce a magnetic field, whose strength is controled by the current in the wiire, to bend the electron beam. Electgrons in a magnetic field move in a circular path at right angles to the direction of the magnetic field.

[Telecolor 3007]

No I got the ideea! Thank for the explenations!