Cro-doubler

Description: The IC1a, IC1b, and IC1c components of the quad two-input NAND gate 4011 are configured as an astable multivibrator, while IC1d functions as an inverter. Terminals 3 and 11 of the 4011 generate square waves that are out of phase with each other. The square waves, denoted as eP, at the output of IC1a, are processed through differentiator C4R13 to create positive and negative pulses, referred to as e1. The dual operational amplifiers of the LM358 serve as two gated amplifiers for signals e1 and e2, which are input through terminals 2 and 6 to be displayed simultaneously on the CRO screen. The square waves eP and eP are utilized to control IC2a and IC2b at terminals 3 and 5 of the LM358, respectively.

Resistances R9 and R10 are preadjusted to ensure that one operational amplifier reaches saturation while the other operates as a normal amplifier. This configuration allows for the alternating amplification of signals e1 and e2, resulting in two distinct traces being shown on the screen. The resistance R12 is adjustable to modify the vertical separation between the two traces. A suitable capacitor value for C1 should be selected using switch S, and the potentiometer R1 should be adjusted accordingly. The frequency of the square waves can be varied from 1 to 106 cycles per second. This adjustment is crucial for stabilizing the waveforms displayed on the screen. The circuit operates with a common supply voltage of 6 V.

The circuit utilizes a quad two-input NAND gate (4011) configured in an astable multivibrator arrangement, which generates two square wave outputs that are 180 degrees out of phase. This configuration allows for the continuous oscillation of the output signals. The differentiator circuit composed of capacitor C4 and resistor R13 converts these square waves into sharp pulses, which are essential for the subsequent amplification stages.

The LM358 dual operational amplifier is employed for its versatility in signal processing. Each op-amp is configured to amplify the differentiated signals e1 and e2. The pre-adjustment of resistors R9 and R10 is critical for ensuring that one op-amp saturates, allowing for maximum signal amplification, while the other maintains linear operation. This design choice enables the display of two distinct traces on the CRO, providing a visual representation of the alternating signals.

The variable resistor R12 permits fine-tuning of the vertical spacing between the two output traces, allowing for clear differentiation on the display. The selection of capacitor C1 is facilitated by switch S, which enables the user to adjust the timing characteristics of the circuit. The potentiometer R1 is used to further refine the circuit's response, ensuring that the output frequencies can be smoothly varied across a wide range, from 1 Hz to 106 Hz. This capability is essential for applications requiring precise waveform analysis.

Overall, the circuit is powered by a stable 6 V supply, ensuring reliable operation of all components, including the NAND gate and operational amplifiers. The design is suitable for educational purposes and practical applications in waveform generation and analysis.IC1a, IC1b, and IC1c of the quad two-input NAND gate 4011 are connected as an astable multivibrator; IC1d is connected as an inverter. Terminals 3 and 11 of the 4011 produce square waves with opposite phases. The square waves, eP, at the output of IC1a, passing through differentiator C4R13, then form positive and negative pulses, e,.

The dual op amps of the LM358 are used as two gated amplifiers for singles e1 and e2 and fed through terminals 2 and 6, to be displayed simultaneously on the CRO screen. The two opposite-phase square waves ep and ep are used to gate IC2a and IC2b at terminals 3 and 5 of the LM358, respectively.

Resistances R9 and R10 are preadjusted so that one op amp is driven to saturation while the other works normally as an amplifier. Thus, they will amplify signals e1 and e2 alternately, and two separate traces will be displayed on the screen.

Resistance R12 can be varied to adjust the vertical separation of the two traces. Select a suitable value for C1 with switch S, and adjust the pot of Rl. The frequency of square waves can be varied from 1 to 106 cps. This process is necessary for stabilizing the waveforms displayed on the screen. A common supply of 6 V is used in the circuit.