741 Op-Amp Self assemble kit
The “XL741” Discrete Operational Amplifier kit from Evil Mad Scientist Laboratories is a faithful and functional transistor-scale replica of the muA741 op-amp integrated circuit, the classic and ubiquitous analog workhorse. An Operational Amplifier, or “op-amp” as they are commonly known, is one of the most useful and common types of analog electronic circuit building blocks and the XL741 kit was designed by Eric Schlaepfer, in collaboration with Evil Mad Scientist Laboratories is lovingly designed to resemble one. The XL741 kit is sold as an easy-to-build soldering kit. It includes the circuit board, resistors, transistors and capacitor that make up the electrical circuit as well as printed assembly instructions. The kit also comes complete with the “IC Leg” stand, and 8 color coded thumbscrew terminal posts. Basic electronic soldering skills are required, but no additional knowledge of electronics is presumed or required and it should take about an hour to build. The XL741 circuit is a direct implementation of the “equivalent circuit” from the original Fairchild muA741 datasheet. It comes with terminal posts and solder points so that you can actually connect to it and build up classic and functional op-amp circuits.
Op-Amps or Operational Amplifiers
A operational amplifier has two inputs an inverting input that is 180 degrease out of phase of the output and a non-inverting input that is in-phase with the output. An op-Amps input impedance is very high. Buy Operational amplifiers
List of common Op-amps:
LM324 (quad opamp):
Low Power Quad Operational Amplifier
The LM324 can operate on a single voltage power supply. this op-amp has 4 independent operational amplifiers in a single chip.
The 741 op-amp is a common general purpose Operational amplifier.
This op-amp is useful as it has short circuit protection and high gain over a wide voltage( up to 18V max).
This opamp is now obsolete
the LM308 was a precision operational amplifier. It had a wide voltage range up to 18V and could run off an unregulated power supply.
The LM386 Operational amplifier is a Low voltage Audio Power amplifier and is some times refered to as a “audio op amp”. it also has a wide voltage range from 4V-12V or 5v to 18V Low distortion and Low current drain. This op amp was designed to be used as a low voltage product to be used in consumer products the Gain is set internally 20 20 to keep external components to a minimum, lowering product costs. The LM386 is an ideal product for basic audio circuits.
Types of OP amp Circuits:
In this configuration the Input signal is connected to the Inverting input on the Op-amp and the output is fed back 180 degrees out of phase into the inverting input(negative feedback) this reduces the gain of the amplifier. If Rf = Rin then the gain will be -1 and the op-amp will act as a simple inverter. The input impedance(z) is relatively low and is determined by Rin.
In a Non-Inverting Op-Amp Input signal is used as a reference voltage on the non-inverting input of the op-amp. and the inverted input is basically referenced to ground. This circuit has a very High impedance(z) somewhere between 1M to 1T ohms.
Vout = (V2-V1)(Gain)
A differential amplifier will determine the difference between two input voltages andoutput the amplified difference that is determined by the external resisters in the circuit. If all the resisters are equal then the Gain will = 1. To adjust the gain you will need to change the Resistance of both the input voltage dividers equelly.
Vout = Vin
An opamp voltage follower has a very useful characteristic as the input Impedance is extremely high and in-essence will isolate the input signal voltage from the outputsignal. this will reduce the loading effect on the signal source.
Schmitt trigger(“thermionic trigger):
Comparator implementation of a schmit trigger using positive feedback loop.
Inverted Schmitt trigger
Non-Inverted Schmitt trigger