This is a fantastic circuit for self-protection. In case a burglar intrudes your house, you can use this security circuit as a weapon for self-protection by giving a mild electric shock to the attacker. This circuit comprises astable multivibrator, inverter, and voltage quadrupler sections. The astable multvibrator is designed for 1 kHz with a 9V DC supply. The inverter section consists of switching transistors and an inverter transformer. The primary of transformer is of 9V-0-9V and the secondary is of 100V, 100mA. For compatibility, a driver transformer that is used in radio is used as the inverter transformer. The secondary output current of 100 mA gives a good enough shock to human body. Fig. 1: Schematic diagram of toy shock gun The astable multivibrator consists of two BC107 transistors (T1 and T2), two 0.01µF capacitors (C1 and C2), two 4.7-kilo-ohm resistors (R1 and R4), and two 72-kilo-ohm resistors (R2 and R3). A squarewave output of 1 kHz (with a phase shift of 180 degrees) ...