Description. Here is the circuit diagram of a 30V/3A adjustable regulator using the LM723 IC from the National Semiconductors. LM723 is an integrated series regulator whose output voltage can be adjusted between 2V and 37V. The IC by itself can deliver an output current of 150mA and the maximum input voltage to the IC is […]
Description. The circuit shown here is of a TV antenna booster based on the transistor BF180. The circuit operates in the UHF band and has a gain of 15dB. Capacitors C2,C3 C4 ,C5 and inductors L3, L4 forms a UHF band pass filter. The input signal is fed to the emitter of Q1 through this
Description This is the schematics of a low cost mic mixer that can be assembled from the components in your junk box.This two channel mike mixer is designed for handling high impedance dynamic microphones.Transistor Q1 can be any general purpose pnp transistor like BC177 or BC157B. Resistor R5 biases the transistor while R3 and R4
Description. This is a very versatile voice modulator circuit using IC HT8950A from Holtek Semiconductors. The IC is capable of creating 7 upward or downward steps on the frequency of the input voice at a rate of 8Hz. There is also two special variation effects namely Vibrato mode and Robot mode. This circuit finds a
Description. This is a simple and easy to construct digital dice circuit. The circuit is based on a single IC, CD4060B.The dice consists of six LEDs marked D1 to D6.The number of LEDs glowing indicates the numeral. The heart of this circuit is 14 stage binary ripple counter IC CD4060B.The IC also has a built-in
Description. Here is the circuit diagram of an ultrasonic mosquito repeller.The circuit is based on the theory that insects like mosquito can be repelled by using sound frequencies in the ultrasonic (above 20KHz) range.The circuit is nothing but a PLL IC CMOS 4047 wired as an oscillator working at 22KHz.A complementary symmetry amplifier consisting of
Description. Here is a simple circuit using IC LM 350, which can be used for charging 12V lead acid batteries. This circuit is perfect for “constant charging” 12V lead acid batteries. The circuit is designed as a constant voltage source with a negative temperature coefficient. The transistor Q1 (BD 140) is used as the temperature
Description. Here is a simple but effective intercom circuit that is based fully on transistors.The circuit is based on a three stage RC coupled amplifier. When the pushbutton S2 is pressed, the amplifier circuit wired around T1 & T2 becomes an astable multivibrator and starts producing the ringing signals. These ringing signals will be amplified
Description. Here is a versatile remote controlled appliance switch that can ON or OFF any appliance connected to it using a TV remote. Â IR remote sensor IC TSOP 1738 is used for recieving the signal. Normally when no signal is falling on IC3 the output of it will be high.This makes Q1 OFF.When a signal
Description. The circuit given here can be used to control the brightness of low power incandescent lamps. The circuit is based on IC NE555 which is wired as an astable multivibrator with variable duty cycle. The output of IC is connected to the base of transistor Q1.The Q1 drives the lamp. The duty cycle of
Description. This is a simple approach to obtain a 12V and 5V DC power supply using a single circuit. The circuit uses two ICs 7812(IC1) and 7805 (IC2) for obtaining the required voltages. The AC mains voltage will be stepped down by the transformer T1, rectified by bridge B1 and filtered by capacitor C1 to
Descrption. This is a simple circuit in which the glowing LED can be switched OFF just by a puff. A condenser mic (M1) is used to sense your puff. When the push button S1 is pressed, the transistors Q2 and Q3 wired as latching pair gets activated and drives the LED to glow. The LED
Description. This simple circuit can be used as an aid for sensing the distance between the rear bumper of the car and any obstacle behind the car. The distance can be understood from the combination of the LEDs (D5 to D7) glowing. At 25cm D7 will glow, at 20 cm D7&D6 will glow and at
Description. Here is a simple yet powerful circuit that can be used for flashing 12V lamps especially that is used on automobiles.The flashing circuit is based on transistor Q1(BC557) and MOSFET Q2 (IRF530) where the Q2 provides the necessary drive for the lamp.Any number of bulbs can be flashed using this circuit provided that the
Description. Here is a simple circuit based on two transistors that can be used to control the speed of a 12 V DC fan depending on the temperature.A thermistor (R1) is used to sense the temperature. When the temperature increases the base current of Q1 (BC 547) increases which in turn decreases the collector voltage
Description. This timer circuit can be used to switch OFF a particular device after around 35 minutes. The circuit can be used to switch OFF devices like radio, TV, fan, pump etc after a preset time of 35 minutes. Such a circuit can surely save a lot of power. The circuit is based on quad
 Description. Here is a simple circuit that can be used to pulse an LED or a low power filament lamp. The effect is such that the LED lights up from OFF state gradually and then dims gradually. Such a circuit is very useful in decoration purposes. The circuit is nothing but a triangular wave generator
Description. The circuit given below shows a negative reference voltage supply.The reference voltage can be set to precise values by R2. The circuit operates in the same manner as the positive reference voltage supply circuit shown previously.The circuit is nothing but an inverting DC amplifier based on IC uA741.The circuit operates on a negative power
Description. The circuit given below is a variable positive voltage reference supply.The reference voltage can be set to precise values by R2.Basically the circuit is a DC amplifier based on op-amp uA 741.The negative feedback is given via the zener diode. Circuit diagram with Parts list. Notes. Assemble the circuit on a good quality PCb
AIM To add two 8 bit numbers using 8085 microprocessor PROGRAM MV1 C,00 LDA 4200 MOV B,A LDA 4201 ADD B JNC LABEL1 INRC LABEL1:STA 4202 MOV A,C STA 4203 HLT SAMPLE OUTPUT ADDRESS DATA INPUT/OUTPUT 4200 15 Input 4201 27 Input 4202 3C Output(sum) 4203 00 Output(carry) RESULT A program to add two 8
                                             In our experiments we used Micro 85 EB trainer kit from Vi Micro systems. The steps involved in doing programs in trainer kit are summarized below.  1.Write the program 2.Prepare the hex code of the program 3.Enter the hex code to trainer kit in suitable locations(eg:From 4100 H) 4.Give sufficient data for
AIM To design and setup a UJT relaxation oscillator. COMPONENTS AND EQUIPMENTS NEEDED 1. UJT (2N2446) 2. Resistors 3. Capacitor 4. CRO 4. DC power supply CIRCUIT DIAGRAM DESIGN Take Vp= 10 V and f =1 KHZ Vp= η VBB+ Vd (Vd can be neglected) VBB=15V (Assume η = 0.62) From data sheet valley point
AIM  To plot the characteristics of UJT (2N 2446) and to determine the intrinsic stand off ratio from the graph.  COMPONENTS AND EQUIPMENTS REQUIRED  1. UJT 2. Resistors 3. Voltmeter 4. Ammeter 5. Rheostat 6. Power supply  CIRCUIT DIAGRAM                                                                                                                           EQUIVALENT CIRCUIT OF UJT   THEORY        UJT is
AIM   To plot the characteristics of BC 107 transistor and to find 1. Dynamic input resistance 2. Dynamic output resistance 3. Common emitter current gain  COMPONENTS AND EQUIPMENTS NEEDED  1. Transistor 2. Variable power supplies 3. Resistors 4. Voltmeters 5. Ammeters  CIRCUIT DIAGRAM THEORY          A transistor is a 3 terminal
AIM To design and setup an RC integrator and differentiator circuits  COMPONENTS AND EQUIPMENTS REQUIRED 1. Capacitors 2. Resistors 3. Signal generator 4. CRO  CIRCUIT DIAGRAM AND DESIGN 1.     DIFFERENTIATOR WITH INPUT FREQUENCY 1 KHZ Input voltage is 20 v pp. DESIGN  RC<0.0016T; Take R= 5.6 K (To avoid the loading
