TREE

The circuit is intended for carrying out harmless experiments with high-voltage pulses and functions in a similar way as an electrified fence generator. The p.r.f. (pulse repetition frequency) is determined by the time constant of network R1-C3 in the feedback loop of op amp IC1a: with values as specified, it is about 0.5 Hz. The stage following the op amp, IC1b, converts the rectangular signal into narrow pulses. Differentiating network R2-C4, in conjunction with the switching threshold of the Schmitt trigger inputs of IC1b, determines the pulse period, which here is about 1.5 ms. The output of IC1b is linked directly to the gate of thyristor THR1, so that this device is triggered by the pulses. The requisite high voltage is generated with the aid of a small mains transformer, whose secondary winding is here used as the primary. This winding, in conjunction with C2, forms a resonant circuit. Capacitor C3 is charged to the supply voltage (12 V) via R3.When a pulse output by IC1b trigg...

The circuit is intended for carrying out harmless experiments with high-voltage pulses and functions in a similar way as an electrified fence generator. The p.r.f. (pulse repetition frequency) is determined by the time constant of network R1-C3 in the feedback loop of op amp IC1a: with values as specified, it is about 0.5 Hz. The stage following the op amp, IC1b, converts the rectangular signal into narrow pulses. Differentiating network R2-C4, in conjunction with the switching threshold of the Schmitt trigger inputs of IC1b, determines the pulse period, which here is about 1.5 ms. The output of IC1b is linked directly to the gate of thyristor THR1, so that this device is triggered by the pulses. The requisite high voltage is generated with the aid of a small mains transformer, whose secondary winding is here used as the primary. This winding, in conjunction with C2, forms a resonant circuit. Capacitor C3 is charged to the supply voltage (12 V) via R3.When a pulse output by IC1b trigge...

Most of the mobile phone complaints are related to the power supply. This is mainly because of improper charging and use of non-recommended chargers and low-quality batteries. Depending upon the make and model, the charging time of mobile phones varies from 1 hour to 3 hours. The charging current is also different for different models. So it is better to use the charger specified by the company only. Equipment for measuring the capacity or the backup time of a battery are not readily available in the market. But by measuring the charging and discharging currents, the approximate backup time of a battery can be found out. For example, charge a battery of 4.8V, 400mA rating for 1 minute and check whether it can discharge for 1 minute through a 400mA torch bulb. If the battery is discharged fully, it would not get charged again through a normal charger. The battery would require an initial charge or  boosting. Here’s a multipurpose circuit (see Fig. 1) for battery boosting as well as ...