Pulse Generator And Signal Tracer Circuit

This is a simple circuit that is can generates narrow pulses at about 700-800Hz frequency. The pulses, containing harmonics up to the MHz region, can be injected into audio or radio-frequency stages of amplifiers, receivers and the like for testing purposes. This is the figure of the circuit;

This circuit is work if Q1 & Q2 form a complementary astable multivibrator, whose operating frequency is set mainly by R3, C2 & C3 values. Output pulses are taken at Q2 Collector and applied to the probe by means of decoupling capacitor C1. D1 provides a symmetrical shape for the output waveform. If an earclip or headphone jack is plugged into J1, the connection from Q2 Collector and C1-C2 is broken by the switch incorporated into J1: in this case the circuit becomes a two-stage amplifier.

Positive Voltage Doubling Circuit using ICL7660 Voltage Doubler

This is a circuit for voltage doubler that can be connected to function as voltage doublers in order to generate output voltage. The schematic herein appears positive voltage doubling circuit using the ICL7660. This is the figure of the circuit;


In this circuit, the pump inverter switches of the ICL7660 is used to charge C1 to a voltage level of the supply voltage (V+) and the forward voltage drop (Vf) of diode D1. Voltage on C1 plus the supply voltage is applied through diode D2 to capacitor C2. And the source resistance of the output will depend on the output current.

High Performance Sawtooth Generator Circuit

This is a design for sawtooth generator circuit. The advantage of this circuit is low cost and produces an auxiliary square wave at the same frequency. This circuit can be used to sweep the frequency of another generator. This is the figure of the circuit.


A voltage-controlled current source is formed by IC1 with R1 and Q1. The C1 is discharged by current Io until it’s voltage is less than 1.66V. It will swing its output to 5V and trips the IC2A comparator. The C1 is charged by current through the diode-connected transistor (Q2) until its voltage reaches 3.33V, so the IC2A output to swing back to ground. The output frequency is determined by :

fOUT = (3(5V +VC)/5V)(1/R1C1).

We can set the fOUT as high as desired by adjusting the values of C1and R1, subject to the limitations of comparator IC2A’s slew settling and rate time. The frequency range over which it can operate determined by generator’s linearity.

Random Noise Generator

This circuit is often needed in testing any type of electronic systems such as filter, audio, or RF communication. The circuit presented here generates an RMS amplitude regulated noise source with selectable bandwidth. This circuit is work based on op amp. This is the figure of the circuit.


With 1 KHz to 5 MHz decade ranges selectable bandwidth and 300mV RMS output, this noise generator is suitable for wide range of application. Noise is generated by D1 that is AC coupled to A2, an amplifier with broadband gain 100. The output of A2 is fed to a simple selectable low-pass filter. The filter’s output is applied to LT1228 operational trans-conductance amplifier A3. A3’s output feeds current feedback amplifier LT1228 A4. A4’s output, which is also the circuit’s output, is sampled by the A5-based gain control configuration. This closes a gain control loop to A3. A3’s ISET current controls gain, allowing overall output level control.

High Frequency Waveform Generator Using MAXIM IC

This is the circuit of waveform generator. Waveform generator is very useful in electronic experiment and design. This circuit is generates sine wave oscillation, but actually we can modify the circuit to generate triangle or square wave function. This is the figure of the circuit.


This circuit is based on MAXIM IC. This integrated circuit chip gives complete function to build a waveform generator/function generator. Here some of modifications that can be used to build a complete waveform generator circuit:

· The circuit can be used to generate square wave, triangle, or sine wave by programming the pin inputs (A0: pin 3, A1:pin 4).
o A0 A1 WAVEFORM
o X 1 Sine wave
o 0 0 Square wave
o 1 0 Triangle wave

· The frequency can be controlled using current. If we disconnect the 20k RIN from REF (pin 1) and connect it to a DAC, then we can control the frequency using microcontroller or digital interface. We can even control the chip using a quartz crystal (PLL) by controlling the current using a phase comparator output that compares the sync output (pin 14 of MAX038) and a reference clock from quartz crystal oscillator.