SU78854A1 - A method of enhancing small direct currents or voltages - Google Patents

Description

The present invention is a method of amplifying small constant currents flowing in high-resistance circuits, consisting in the periodic charging and discharging into the grid of an amplifying lamp grid by a fraction of the amount of electricity accumulating in the primary circuit.

Methods for using the periodic charge and discharge of a capacitor to obtain charge current in an external circuit are known and used to accurately measure the frequency in the range of sound frequencies.

Also known are DC amplifiers with intermittently breaking contacts in the primary winding of the input transformer. Such amplifiers have a number of drawbacks.

The drawbacks of direct current amplifiers force one to pre-convert the amplified current into alternating or pulsating, which is usually achieved by detuning the balance of the alternating current bridge, amplified by direct current. The use of electronic tubes in ka. the number of controlled elements leads to instability of the amplification of small direct currents and the dependence of the gain on the lamp operation mode. Eliminating this drawback with a low-m input of the amplifier is achieved by converting the current to the first amplification stage by modulating the amplified current.

The proposed method differs from the above in that it makes it possible to use a periodic charge and discharge of a capacitor in the grid circuit of an amplifying lamp for amplifying small direct currents flowing in high-resistance circuits. This process of charging and discharging a capacitor can be performed by a mechanical, electronic, ionic or liquid switch.

The attached drawing shows the electrical circuit of the device.

The measured direct current, for example, the current of the ionization chamber K flows through a large resistance R, shunted by capacitance Cc. The capacitance Ci is charged to a value (at a relatively long constant time) and through, for example, a well-isolated contact vibrator P periodically charges

517

low capacitance C, which is the input capacitance of the amplifier dc current. In the other extreme position, the contact of the vibrating relay P periodically discharges the capacitance C. In this case, the grid of the first lamp L of the stabilized amplifier is excited by current pulses, the amplitude of which is proportional to E and, therefore, proportional to /.

The vibrator relay can be controlled from an alternating current source (for example, from an amplifier's heating circuit) or from a direct current circuit, for which it must be provided with additional contacts. Instead of a mechanical switch, a liquid, electronic, ion and the like switch can be used.

Further amplification levels can form either linear

an amplifier with an amplitude voltmeter at the output, or an integrating amplifier with a diode voltmeter at the output. Voltmeters can be calibrated directly in the values of

The subject of the invention is a method of amplifying small direct currents or voltages, characterized by using a periodic charge and discharge of a capacitor in the grid circuit of an amplifying lamp, part of the amount of electricity accumulating in the source of amplified currents in a circuit consisting of resistance and capacitance, And the capacitor can be discharged by a mechanical, electronic, ionic or liquid switch.