TL084 JFET Op-amp Amplifiers

Overview of TL084 IC

The TL084 is a high-speed J-FET input quad operational amplifier in a monolithic integrated circuit that incorporates well-matched, high-voltage J-FET and bipolar transistors. High slew rates, low input bias and offset currents, and a low offset voltage temperature coefficient characterize the device. In general, the TL084 op-amp is employed in audio systems because it’s a low-noise operational amplifier that really is inexpensive. In this article, we are going to discuss 3 “TL084 JFET Op-amp Circuits”.

Features of TL084 IC

The minimum operating voltage is 7V
Input bias current is 20pA
The input offset voltage is 3mV
CMRR or common-mode rejection ratio is 86dB
The gain is 200 V/mV
Bandwidth is 4MHz
The typical range of operating voltage is +18V to -18V
Protection from output short circuit

Pin Configuration

Pin No	Pin Name/Description
1	Output pin
2	Inverting input pin
3	Input non-inverting pin
4	Positive supply rail (Vcc)
5	Non-inverting input pin
6	Inverting input pin
7	Output pin
8	Output pin
9	Inverting input
10	Non-inverting input
11	Negative supply rail (Vcc)
12	Non-inverting input
13	Inverting input
14	Output

Output Pins: These pins are the four op-amp’s output pins
Input Inverting Pins: These pins are the four Op-Amps input inverting pins
Input Non-Inverting Pins: These pins are the four Op-Amps input non-inverting pins
Vcc (+): This is the Op-Amp’s positive supply rail
Vcc (-): This is the Op-Amp’s negative supply rail

Hardware Required

Infrared Voice Communication Circuit

S.no	Component	Value	Qty
1.	Transistor	2N2222	2
2.	Resistor	220, 1K, 10K, 100K, 220K, 220 Ohm	4, 1, 2, 1, 1
3.	Capacitor	0.1uf, 220uf	2,1
4.	IC	TL084	2
5.	LED & MIC	–	1,1
6.	Variable Resistor	10k	1

Low-Z Microphone Preamp Circuit

Sr No:	Components	Value	Qty
1	Resistor	1k, 100k	2, 2
2	Transformer	–	1
3	IC	TL084	1
4	Buzzer	–	1
5	Speaker	8 ohm	1

Low Dynamic Microphone Preamp Circuit

Sr No:	Components	Value	Qty
1	IC	TL084	1
2	Capacitor	1uF	3
3	Resistor	10k, 1k, 100k	1, 2, 1
4	Variable Resistor	1M	1
5	MIC	–	1

1. Infrared Voice Communicator Circuit

Working Explanation

There are two sections of this infrared voice communicator circuit. There is a transmitter to convert a speech to a signal. For this, we employ the Dynamic microphone preamplifier. Then, using the Q1 transistor, we drive a stronger signal to the infrared LED, to convert the signal into infrared light. We adjust the potentiometer VR1 to modify the quality of the sound or the current to LED1. resistor R5 restricts the maximum current to 40mA. The phototransistor converts an infrared light signal to an audio signal as the receiver. The signal is then amplified by IC1/2 to a greater level than the power amplifier’s input.