'How to build a two valve set', No 10, Godfrey Philips cigarette card, 1925.
© Science Museum / Science & Society Picture Library
The reverse of the card reads: 'Reaction condenser Connections (Contd). The connection fromthe fixed vanes of the reaction terminal is made to the same terminal on the H F choke that is wired to the anode terminal of the first valve holder. The connection is indicated by the finger which is shown touching the wire. The grid leak of 2 megohms (Dubilier) is also shown in the clips provided on the grid condenser.'