Schematic Diagrams

Useful schematic and wiring diagrams. ✔ ✔ Enjoy electronic circuits, let your idea comes to hardware

pre amplifier

55MHz Scope Sensitivity Amplifier

Scope sensitivity amplifier is a vital front-end signal processing for every scope instruments. The function of this circuitry is simple: amplify the signal with a consistent/stable gain without altering the waveform. A stability of its gain make it possible to make a precise volts/div scaler with no drift in time and ambient temperature. The requirement […]


HiFi pre-amplifier circuit diagram with low noise output

This is a HiFi pre-amplifier circuit diagram with low noise output. Very wide range frequency from about 10Hz until up to 100Khz  will be gained by this preamplifier for maximum audio performance. Here the response of the preamp’s frequency and phase: Here the diagram of total noise at output, measured with 600R load: circuit by […]


Simple Mic Pre-Amp based LM358 circuit diagram

Here the simple audio mic pre amplifier circuit based on single IC LM358. The circuit is very simple, inexpensive and easy to built. Component Parts List:R1, R3, R4 = 10KR2 = 1KR5 = 100K-1M PotensiometerC1 = 0.1uFC2 = 4.7uF/16VIC1 = LM358 dual op-amp single supplyMic = Electret Microphone Notes: Use R5 to adjust the gain […]

Guitar Pre-Amp with JFET 2N5457 circuit diagram

Designed by Don Tillman, this guitar pre-amp circuit design is dedicated for people who don’t like op-amps. This circuit is a discrete JFET pre-amp design, use 2N5457 as the main component. It has low noise, low distortion, low feedback, overloads gracefully, is small, etc. Overall gain is 3db (2X) or so. It uses about 1/2 […]


Tube Head circuit diagram

This is a simple and low cost Tube Head Vacuum Tube pre-amp circuit designed bu PAiA electronics: Vcc – Pin 1 IC1+12v – Pin 8 IC2, IC3, IC4-12v – Pin 4 IC2, IC3, IC4Ground – Pin 8 IC1 IC1 – 4049 CMOS Hex Inverting BufferIC2, 3, 4 – 5532 Dual Low-Noise OpAmpD1, 2 – 1N4001D3, […]


Current Amplifier Using CA3140 Op-Amp

Current amplifier application need very low input bias current, and CA3140 is one of suitable op-amps for this purpose. The circuit’s schematic diagram is shown in the figure below. In the circuit, low current is supplied at the input potential as the power supply to load resistor RL. When the load current is monitored by […]

Balanced Input Microphone Pre-Amplifier, High Quality Audio For Long Distance Wiring

Balanced input has three connections, ground, positive signal, and negative signal. When we trace the signal using oscilloscope, if we take the ground as the reference, then the negative signal and the positive signal has similar shape but with inverted polarity. If we measure the signal between positive and negative output, the we have two […]

Battery Powered Electret Microphone Pre-Amplifier

Here is a schematic diagram of electret microphone pre-amplifier using LMV721 op-amp. because the LMV721 has low noise and low power features, it would be an ideal choice for  battery powered microphone preamplifier. The LMV721 is connected as an inverting amplifier. Resistors, R1 =R2 = 4.7k, sets the reference at mid point between VCC = […]

Gramophone Pre-Amp: A Pre-Amplifier with RIAA Response Curve

Recording Industry Association of Ameria (RIAA) has developed the recording standard of response curve for their recording. This curve is developed to optimize the gramophone recording response for lowest signal-to-noise ratio for gramophone technology. Because the tape recording response is not linear, the pre-amp for gramophone playback pickup should have such  response that restore the […]

Two Stage Phono Pre-Amplifier with Very Accurate RIAA Response Curve

To produce a pre-amplifier with accurate RIAA response, this circuit use two stages of amplifier. This circuit is more complex than single op-amp RIAA pre-amp, but the performance is excellent in terms of accurate frequency response. Here is the schematic diagram of the circuit. The circuit uses LM833 high performance op-amp from National Semiconductor, giving […]

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