Artificial Plate Battery
Posted by BlackMASK on November 02 2009 12:51:40
Plate batteries for old tube radios are today only available with difficulty. However, step-up controllers for low DC voltages are everywhere. The circuits of these IC’s are, however, affected by disadvantages and complex wound inductance are needed. A further disadvantage of this solution is the transducer frequency; poor placing can cause audible interference.
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Introduction
Plate batteries for old tube radios are today only available with difficulty. However, step-up controllers for low DC voltages are everywhere. The circuits of these IC's are, however, affected by disadvantages and complex wound inductances are needed. A further disadvantage of this solution is the transducer frequency; poor placing can cause audible interference.
Solutions
I solved the issue of inductances with the employment of standard chokes, which are to be received with each electronics sender. The problem of the interfering radiation is solved by shielding in a sheet-steel housing.
The circuit
As automatic controller, an MC34063 is used. The circuit corresponds to the standard application of the manufacturer up to the filters. Inductances are normal chokes. They do not have the disadvantage that the efficiency of the circuit are so high (75%) - however for it they are well available and produce relatively few disturbances.
The rectifier diode must be absolutely a nearly Recovery diode, otherwise one regains the switching peaks of the diode on DC voltage.
The circuit supplies an output voltage of 90V and 11mA in this configuration with 6V supply.
(Note:increasing the supply voltage should also increase the output voltage)
With the remote entrance the circuit can be activated or deactivated over the filament voltage of the radio. Because with most old radios only the filament voltage is switched. The Jumper JP1 makes it possible to activate or deactivate this function. In the deactivated condition the automatic controller starts immediately, if the voltage is applied.
As a power supply I use 6 V 1.3Ah Panasonic gel-cell. This gives about 5 hours of use (which seems rather low! Ed.).
With the potentiometer R7 the output voltage of approx. can. 60 V to 90 V to be regulated.
Click here to download the detail description of this project along with PCB layout, schematics and images.