Simple Precision full wave Rectifier Circuit Diagram

The circuit provides accurate full wave rectification. The output impedance is low for both input polarities, and the errors are small at all signal levels. Note that the output will not sink heavy current, except a small amount through the 10K resistors. Therefore, the load applied should be referenced to ground or a negative voltage. Reversal of all diode polarities will reverse the polarity of the output

Since the outputs of the amplifiers must slew through two diode drops when the input polarity changes, 741 type devices give 5% distortion at about 300 Hz.


Precision full wave Rectifier Circuit Diagram

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Variable Sine Wave Oscillator Circuit

A Sine wave oscillator or a Wien bridge oscillator can be made variable by using two frequency determining parts that are varied simultaneously at high tracking accuracy.
High quality tracking potentiometers or variable capacitors are, however, expensive and difficult to obtain. To avoid having to use such a component, this oscillator was designed to operate with a single potentiometer.

The output frequency, fo, is calculated from fo = 1/(2pi.RC.rootAlpha) where R=Rz=Rz=R4=Rs, C=Ci:C2, and a=(P1+R1)R. Preset P2 allows adjusting the overall amplification such that the output signal has a reasonably stable amplitude (3.5 Vpp max.) over the entire frequency range.

The stated components allow the frequency to be adjusted between 350 Hz and 3.5 kHz. Other frequency ranges are readily defined with the aid of the above formula, although it should be noted that the upper frequency limit is determined mainly by the gain-bandwidth product of the opamps Type OP-221 and TLC272.

The current consumption of the oscillator depends on the type of opamp used. The following values were measured: OP-221: 0.5 mA; TLC272: 2mA; TLO72: 2mA. The construction of the oscillator should present very few problems since a readymade circuit board is available through our Readers Services.

Circuit diagram of a sine wave oscillator is shown below:

                                           

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Sine Wave Generator 1KHz Frequency

This is iKHz sine wave generator schema built based on configuration of inverted Wien bridge (see C1-R3 & C2-R4). R5 and R7 used for output amplutide setting. Set R5 to read 1V RMS on an Audio Millivoltmeter connected to the output with R7 rotated fully clockwise, or to view a sinewave of 2.828V Peak-to-Peak amplitude on the oscilloscope.

Component list:

R1____________5K6 1/4W Resistor
R2____________1K8 1/4W Resistor
R3,R4________15K 1/4W Resistors
R5__________500R 1/2W Trimmer Cermet
R6__________330R 1/4W Resistor
R7__________470R Linear Potentiometer

C1,C2________10nF 63V Polyester Capacitors
C3__________100µF 25V Electrolytic Capacitor
C4__________470nF 63V Polyester Capacitor

Q1,Q2_______BC238 25V 100mA NPN Transistors
LP1___________12V 40mA Filament Lamp Bulb (See Notes)
J1__________Phono chassis Socket
SW1__________SPST Slider Switch
B1_____________9V PP3
Clip for 9V PP3 Battery

Notes:

• The bulb must be a low current type (12V 40-50mA or 6V 50mA) in order to obtain good long term stability and low distortion.
• Using a bulb differing from specifications may require a change of R6 value to 220 or 150 Ohms to ensure proper diagram oscillation.
• With C1, C2 = 100nF the frequency generated is 100Hz and with C1, C2 = 1nF frequency is 10KHz but R5 requires adjustment.
• High gain transistors are preferred for better performance.

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2MHz Square Wave generator Wiring diagram Schematic

With the values shown the schema generates a 2-MHz symmetrical square wave. Changing capacitors Cl and C2 to 0.01 µ¥ results in a frequency of 500 Hz. For the particular integrated diagram and power supply voltages (5.0 V), the reliable operating range of Rl = R2 is 2 k ohm to 4 k ohm.

2MHz Square Wave generator Circuit Diagram

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Ultrasonic Wave Receiver Circuit

Ultrasonic Wave Receiver

Ultrasonic recipients will receive an ultrasonic signal emitted by an ultrasonic transmitter in accordance with the characteristic frequency. Received signal is going through the process of filtering using the frequency band pass filter circuit, with a frequency value that is passed has been determined.


Then the output signal will be amplified and passed to the comparator circuit (comparator) with a reference voltage determined based on the amplifier output voltage when the distance between the sensor mini vehicles with bulkhead / retaining walls to reach the minimum distance for the turn direction. Comparator output can be considered under these conditions is high (logic 1 ), while longer distances are low (logica0). Binary logics are then forwarded to the circuit controller (microcontroller).

The working principle of ultrasonic wave receiver circuit are as follows:

• First - the first received signal will be strengthened first by the circuit transistor amplifier Q2.
• Then the signal will be filtered using a high pass filter at a frequency of> 40kHz by a series of transistor Q1.
• After the signal is amplified and filtered, then the signal will be rectified by diode D1 and D2 series.
• Then the signal through a filter circuit low pass filter at a frequency <40kHz through the filter circuit C4 and R4.
• After that the signal will go through the Op-Amp comparator U3.
• So when there is an ultrasonic signal into the circuit, then the comparator will issue a logic low (0V), which will then be processed by the microcontroller to calculate the distance.

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Radio Wave Alarm Wiring diagram Schematic

This simple schema is sure to have the police beating a path to your door- however, it has the added advantage of alerting you to their presence even before their footsteps fall on the doormat.

Simple Radio Wave Alarm Circuit Diagram :

Notes :

• The schema transmits on Medium Wave (this is the small problem with the police). IC1a, together with a sensor (try a 20cm x 20cm sheet of tin foil) oscillates at just over 1MHz. This is modulated by an audio frequency (a continuous beep) produced by IC1b. When a hand or a foot approaches the sensor, the frequency of the transmitter (IC1a) drops appreciably.
• Suppose now that the schema transmits at 1MHz. Suppose also that your radio is tuned to a frequency just below this. The 1MHz transmission will therefore not be heard by the radio. But bring a hand or a foot near to the sensor, and the transmitters frequency will drop, and a beep will be heard from the radio.
• Attach the antenna to a multiplug adapter that is plugged into the mains, and you will find that the Medium Wave transmission radiates from every wire in your house. Now place a suitably tuned Medium Wave radio near some wires or a plug point in your house, and an early-warning system is set up.
• Instead of using the sheet of tin foil as the sensor, you could use a doorknob, or burglar bars. Or you could use a pushbutton and series resistor (wired in series with the 33K resistor - the pushbutton would short it out) to decrease the frequency of IC1a, so activating the system by means of a pushbutton switch. In this case, the radio would be tuned to a frequency just below that of the transmitter.

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