author: Jonathan Filippi
Read before building:
This device produces high voltage pulses disrupting muscles and nervous system, leaving anyone who touches it in a state of mental confusion. Can be used again ferocious animals or attackers, BUT REMEMBER, this device may be illegal in your state (for eg where I live, these devices are banned). It is quite dangerous for peoples experiencing cardiac problems, and for electronic equipment (like peacemakers), since it generates some RF. Don't attempt irresponsible actions with this device, it is not a toy.
After the introduction let's pass to the circuit.
The 555 IC is wired as a astable to produce square wave with adjustable freq and duty cycle (notice the potentiometers and diode). This square wave is feed to a IRF840 Mosfet (no need of totem transistors since freq is low and the IC has enough current capability to rapidly charge/discharge the gate). As a substitute of the mosfet, a bipolar transistor can be used (and a 100ohm resistor between 555 and base of the transistor). Valid BJT can be BU406, but also smaller BJT can be OK, keep in mind that it must handle at least 2A continuous. The inductive kick snubber isn't needed because the power is low and it is almost totally adsorbed to charge the tank capacitor, in addition since this device is battery operated we don't want to dissipate the power on a resistor but we want it in sparks. With a snubbing network you will experience lower firing rates. USE A PUSHBUTTON SWITCH FOR SAFETY
Construction of T2: this is the real boring part. Since it is unlikely to find it in shops we need to build them. Materials needed: enamel copper wire (0,20 mm or 0,125 mm), ferrite stick, LDPE sheets (0,25 mm). Secure the ferrite stick with a layer of ldpe (polyethilene, as a substitute use electric insulating tape) and glue it (or tape it) Place 200-250 windings on the ldpe (even more windings if the stick is more than 1'), another ldpe layer, another 200-250 windings and so on to finally have 5-6 layers (approx 1000-1400 turns but even more doesn't hurt performance, but be careful for internal arcing that will ruin it). Insulate it again and place the primary winding, 15-20 turns of 1mm wire are just ok, too much windings (too mush resistance and inductance) will lead to smaller current and smaller spike in T2 secondary because of lower rise time,and too few will not saturate the core. I chosen MKP capacitors because they have low ESR and ESL (they are widely used in tesla coils as mmc capacitors).
The spark gap can be simple two crossed (but not touching) 1 mm spaced wires. It acts as a voltage controlled switch, firing when
the voltage is enough to ionize the air between them (turning it to plasma with small resistance). Keep in mind that it would
be wise do place it into a small plastic container and fill with oil letting bubbles out (don't use motor oir or frying oil
but pure mineral oil which has no water in it.
Disclaimer: As i have seen before, IT IS NOT A TOY, DON'T DO ANYTHING STUPID WITH IT. I DON'T ACCEPT ANY RESPONSIBILITY OF DAMAGES DONE TO OTHER PEOPLE OR YOURSELF WITH THIS DEVICE. IF YOU WANT TO BUILD IT YOU MUST ACCEPT THIS CONDITION. Using the procedures described above would prevent you from any damages/troubles. Don't carry it in streets or public places if they are banned in your country, and don't use it near electronic devices. As the wise man says use it like a deterrent, even against animals.
from http://www.electronics-lab.com
Basic UPS Power Supply
source: Andy Collinson
Description
This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply. In the event of electrical supply line failure the battery takes over, with no spikes on the regulated supply.
Notes:
This circuit can be adapted for other regulated and unregulated voltages by using different regulators and batteries. For a 15 Volt regulated supply use two 12 Volt batteries in series and a 7815 regulator. There is a lot of flexibility in this circuit.
TR1 has a primary matched to the local electrical supply which is 240 Volts in the UK. The secondary winding should be rated at least 12 Volts at 2 amp, but can be higher, for example 15 Volts. FS1 is a slow blow type and protects against short circuits on the output, or indeed a faulty cell in a rechargeable battery. LED 1 will light ONLY when the electricity supply is present, with a power failure the LED will go out and output voltage is maintained by the battery. The circuit below simulates a working circuit with mains power applied:
Between terminals VP1 and VP3 the nominal unregulated supply is available and a 5 Volt regulated supply between VP1 and VP2. Resistor R1 and D1 are the charging path for battery B1. D1 and D3 prevent LED1 being illuminated under power fail conditions. The battery is designed to be trickle charged, charging current defined as :-
(VP5 - 0.6 ) / R1
where VP5 is the unregulated DC power supply voltage.
D2 must be included in the circuit, without D2 the battery would charge from the full supply voltage without current limit, which would cause damage and overheating of some rechargeable batteries. An electrical power outage is simulated below:
Note that in all cases the 5 Volt regulated supply is maintained constantly, whilst the unregulated supply will vary a few volts.
Standby Capacity
The ability to maintain the regulated supply with no electrical supply depends on the load taken from the UPS and also the Ampere hour capacity of the battery. If you were using a 7A/h 12 Volt battery and load from the 5 Volt regulator was 0.5 Amp (and no load from the unregulated supply) then the regulated supply would be maintained for around 14 hours. Greater A/h capacity batteries would provide a longer standby time, and vice versa.
from http://www.electronics-lab.com
Description
This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply. In the event of electrical supply line failure the battery takes over, with no spikes on the regulated supply.
Notes:
This circuit can be adapted for other regulated and unregulated voltages by using different regulators and batteries. For a 15 Volt regulated supply use two 12 Volt batteries in series and a 7815 regulator. There is a lot of flexibility in this circuit.
TR1 has a primary matched to the local electrical supply which is 240 Volts in the UK. The secondary winding should be rated at least 12 Volts at 2 amp, but can be higher, for example 15 Volts. FS1 is a slow blow type and protects against short circuits on the output, or indeed a faulty cell in a rechargeable battery. LED 1 will light ONLY when the electricity supply is present, with a power failure the LED will go out and output voltage is maintained by the battery. The circuit below simulates a working circuit with mains power applied:
Between terminals VP1 and VP3 the nominal unregulated supply is available and a 5 Volt regulated supply between VP1 and VP2. Resistor R1 and D1 are the charging path for battery B1. D1 and D3 prevent LED1 being illuminated under power fail conditions. The battery is designed to be trickle charged, charging current defined as :-
(VP5 - 0.6 ) / R1
where VP5 is the unregulated DC power supply voltage.
D2 must be included in the circuit, without D2 the battery would charge from the full supply voltage without current limit, which would cause damage and overheating of some rechargeable batteries. An electrical power outage is simulated below:
Note that in all cases the 5 Volt regulated supply is maintained constantly, whilst the unregulated supply will vary a few volts.
Standby Capacity
The ability to maintain the regulated supply with no electrical supply depends on the load taken from the UPS and also the Ampere hour capacity of the battery. If you were using a 7A/h 12 Volt battery and load from the 5 Volt regulator was 0.5 Amp (and no load from the unregulated supply) then the regulated supply would be maintained for around 14 hours. Greater A/h capacity batteries would provide a longer standby time, and vice versa.
from http://www.electronics-lab.com
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