AUTOMATIC PHASE CHANGER
MUHAMMAD AJMAL P.
As soon as phase-R voltage goes
below 200V, the voltage at inverting
pin 2 of IC1 goes below reference voltage of 5.1V, and its output goes low.
As a result, transistor T1 conducts and
relay RL1 en
D. MOHAN KUMAR
transistors in the input to provide very
high input impedance (1.5 T-ohms),
very low input current (10 pA) and
high-speed switching performance.
The inverting input of IC1 is preset with VR1. In the standby mo
AUDIO AMPLIFIER FOR
M. VENK ATESWAR
pushpull amplifier, each transistor (T2
or T3) gets double the voltage when
Connect the low audio signal from
the stereo system at input terminals A
and B of t
APPLIANCE TIMER-CUM-CLAP SWITCH
collector potential is very near to the
emitter potential, i.e., ground, and
therefore there is no base current to
transistors T7 through R6. Thus, transistor T7 is in cut-off state. The collecto
Ashok K. Doctor
attached. It is useful to relieve headache and muscular pain and revive
frozen muscles that impair movement.
Though it provides muscles stimulation and invigoration, its mainly an
aid in removing celluliti
BELL-CUM LIGHT CONTROLLER
transistors T1 and T2.
IC1 is a 14-stage binary counter and
oscillator IC. In its quiescent state, the
Q13 output (pin 3) is high, which results in conduction of transistor T1 to
cut off transistor T2. Thus the rela
D. MOHAN KUMAR
one attempts to snatch your bag or suitcase. This will draw the attention of other
passengers and the burglar can be caught
In the standby mode, the circuit is
locked by a plug and so
Inverter for Soldering Iron
When you power the circuit using
switch S1, transformer X1 produces
230V AC at its primary terminal. This
voltage can be used to heat your soldering iron.
Assemble the cir
ANTI-THEFT ALARM FOR BIKES
PRAVEEN KUMAR M.P.
of the mobikes horn, while the positive
terminal of the horn is connected to the
positive terminal of the battery via resistor
R1. The energised relay drives the horn,
FOR CAR AUDIOS
Whenever an attempt is made to remove the car audio from its mounting by
cutting its connecting wires, the
optocoupler immediately turns off, as its
LED cathode terminal is h