THE VOLTAGE DOUBLER

Doubling the DC voltage from a single wind secondary can be done. Say the secondary is 6 volts. To get 6 volts, a single diode wherein we only use half wave. To capture both , we need to use a bridge of 4 diodes. The difference is that we got twice the current with the bridge. The DC output will b the same at 6 volts. We can double the DC output by charging two similar capacitors in series, each being "charged" by a half cycle. The caps then are not charging at the same time but alternatively. But the charge is there and being in series, will add up to 12 volts! One end of the seconday line is connected to the junction of the two caps. The other end has two diodes to it with one putting out a +, and the other , a -. The plus goes to the pus of ghe upper cap., the minus to the lower cap. Will tr

y to upload a diagram.

2 tube radio with 1n34 detector

Now, let us study the first tube in details. It is set up as an oscillator and mixer. Look at the osc coil with a tap. The Cathode goes to the tap to gets its ground. But the long side of the coil goes to a grid.So, the tube goes into an oscillation. The frequency is controlled by a variable capacigor anged with the tuner to the antenna coil. The antenna coil is fed into a grid to mix its signal with the local osc. The plate is in series to the primary of the first IFT. The second tube is a straight forward RF amp which amplifies only the 455 Khz intermediate frequency. This makes the radio selective.

2 tube radio

SUPERHETERODYNE RADIO WITH JUST 2 TUBES

Most if not all of us in the chat group are already verify familiar with tube amps. No need for further lessons here. Besides, the hybrid tube amp has for its final amp, an IC. We can limit the tubes to the essential to make a superhet radio. Just 2 tubes. We all have tube amps to amplify the audio. 1. Just use the first two tubes,either the SA and the SK or the BE and BA. 2. Use a 1 amp power supply traffo, 6 or 12 V. 3. The RF tubes do not need a HV, the 12 V secondary an be by putting a voltge double. Or back to back another traffo to get 110 volts isolated. Those 110 volts adaptor will do if the amperae is sufficient. If you an old ps of the Epson printer, it is 32 volts. 4. No need for the rectifier tube then. 5. Audio amp can be a existing tube amp.,or put an IC amp for the audio amp. No need for he power amp tube. 6. The detector cum triode tube can be eliminated, Just use an 1n3 detector diode.

The Tuned Radio Frequency receiver

Armstrong Superheterodyne receiver.