GB2050087A - Pulsed current supply for electric fence - Google Patents

Abstract

An electric fence is supplied with intermittent pulses by a semi- conductor circuit in which all the active components are non-conducting between pulses. At the time an electric shock is produced, all the components are turned on and off again very quickly. Pulses are produced at intervals of between half a second and two seconds, keeping the battery consumption to a very low level. The circuit may use an SCS which becomes conductive when a capacitor C1 is sufficiently charged, turning on further transistor stages and producing a high voltage output at a transformer T2. <IMAGE>

Description

SPECIFICATION Pulsed current electric fencer Description of function: Its function is the same as other fencers: to keep cattle and sheep within the bounds of its wire, by means of them receiving a small electric shock if they touch the fencing wire.

fencing wire.

Its function is different to the capacitor discharge system now widely used. In the C.D. system the capacitor is charged to a high voltage from an oscillator which runs almost continuously. The capacitor is then completely discharged into the primary winding of the high tension output transformer, the secondary winding going to the fencing wire.

PULSED Current System: In the P.C. circuit the amount of electricity used is very much smaller, because all the semi-conductors are in a non-conducting state between its pulses. At the time a pulse is required all the transistors are turned on and off again very quickly, so as to feed a high current at low voltage to the primary of the output transformer, the secondary going to the fencing wire.

The advantage in battery saving is very great, as the only time any major current is being used is for the briefest of time i.e. for the induction of the pulse into the output to the fencing wire, this state being brought about by the complete and precise switching on and off at great speed of the last semiconductor that feeds the output transformer.

Not as in most other types where the semiconductors are running almost continuously and so consuming current.

Description of circuit: TR1 is an S.C.S. and starts in a nonconducting mode. C1 slowly charges via R1.

When the voltage on its anode (A) is a little above its gate (GA), it conducts and a + pulse appears on its cathode (K), because C1 discharged through R2. It does this about every two seconds. R3 conducts this pulse to the base of TR2, which is in a non-conducting mode. It then becomes switched on and its collector current is passed through the matching transformer T1 to drive the last transistor TR3. This too is in a non-conducting mode, and becomes heavily switched on, thereby passing a large current through the primary of transformer 2, and its core becomes magnetically saturated. By this time TR 1 has become non-conducting, as also has TR2 and TR3.

This leads to a rapid collapse of the magnetic field in transformer 2, which provides the electric fencing wire with its high voltage pulse (i.e. a small electric shock if touched).

All transistors then remain in a non-conducting mode for about two seconds, when the same procedure repeats itself.

It has as its working principle that: 1. All the transistors or semi-conductors used to produce its output pulse are in a nonconducting state between its pulses. At the time a pulse is required they are turned on and off again, so that a high current at low voltage is connected to the primary of the output transformer. The secondary being connected to the conductor wire of the fence.

2. The duration and shape of the pulse being matched to the requirements of the' output transformer.

APPENDANT to 1 and 2 above: That no component is used in such a way that a continuous current is passed through it which is not necessary to produce the output pulse.

CLAIMS (24July1980) 1. It is an apparatus for supplying an electric fence with pulses of a high voltage from a transformer energised by a pulsed current transistor circuit powered by small batteries.

2. An apparatus as in Claim 1 where the battery voltage is used to charge a capacitor which when discharged causes all the transistors in the circuit to be made conductive for a brief period only.

3. An apparatus as in Claims 1 and 2 where all the transistors are in a totally nonconductive state between pulses and are coupled in such a way that current pulses turn them on and off, leakage currents in transistors being avoided.

4. An apparatus as in Claims 1, 2 and 3 as described in page 2 with reference to the circuit on page 3.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Pulsed current electric fencer Description of function: Its function is the same as other fencers: to keep cattle and sheep within the bounds of its wire, by means of them receiving a small electric shock if they touch the fencing wire. fencing wire. Its function is different to the capacitor discharge system now widely used. In the C.D. system the capacitor is charged to a high voltage from an oscillator which runs almost continuously. The capacitor is then completely discharged into the primary winding of the high tension output transformer, the secondary winding going to the fencing wire. PULSED Current System: In the P.C. circuit the amount of electricity used is very much smaller, because all the semi-conductors are in a non-conducting state between its pulses. At the time a pulse is required all the transistors are turned on and off again very quickly, so as to feed a high current at low voltage to the primary of the output transformer, the secondary going to the fencing wire. The advantage in battery saving is very great, as the only time any major current is being used is for the briefest of time i.e. for the induction of the pulse into the output to the fencing wire, this state being brought about by the complete and precise switching on and off at great speed of the last semiconductor that feeds the output transformer. Not as in most other types where the semiconductors are running almost continuously and so consuming current. Description of circuit: TR1 is an S.C.S. and starts in a nonconducting mode. C1 slowly charges via R1. When the voltage on its anode (A) is a little above its gate (GA), it conducts and a + pulse appears on its cathode (K), because C1 discharged through R2. It does this about every two seconds. R3 conducts this pulse to the base of TR2, which is in a non-conducting mode. It then becomes switched on and its collector current is passed through the matching transformer T1 to drive the last transistor TR3. This too is in a non-conducting mode, and becomes heavily switched on, thereby passing a large current through the primary of transformer 2, and its core becomes magnetically saturated. By this time TR 1 has become non-conducting, as also has TR2 and TR3. This leads to a rapid collapse of the magnetic field in transformer 2, which provides the electric fencing wire with its high voltage pulse (i.e. a small electric shock if touched). All transistors then remain in a non-conducting mode for about two seconds, when the same procedure repeats itself. CLAIMS It has as its working principle that: 1. All the transistors or semi-conductors used to produce its output pulse are in a nonconducting state between its pulses. At the time a pulse is required they are turned on and off again, so that a high current at low voltage is connected to the primary of the output transformer. The secondary being connected to the conductor wire of the fence. 2. The duration and shape of the pulse being matched to the requirements of the' output transformer. APPENDANT to 1 and 2 above: That no component is used in such a way that a continuous current is passed through it which is not necessary to produce the output pulse. CLAIMS (24July1980)

1. It is an apparatus for supplying an electric fence with pulses of a high voltage from a transformer energised by a pulsed current transistor circuit powered by small batteries.

2. An apparatus as in Claim 1 where the battery voltage is used to charge a capacitor which when discharged causes all the transistors in the circuit to be made conductive for a brief period only.

3. An apparatus as in Claims 1 and 2 where all the transistors are in a totally nonconductive state between pulses and are coupled in such a way that current pulses turn them on and off, leakage currents in transistors being avoided.

4. An apparatus as in Claims 1, 2 and 3 as described in page 2 with reference to the circuit on page 3.