Tag «Pre-Amplifier»

Low Noise Microphone Pre-Amp with Op-Amp

Microphone pre-amp is a very simple circuit, most all low noise op-amp will be sufficient for this circuit (TL071, TL082, OPA371, NE5534, etc). This circuit will be suitable for dynamic microphone, electret microphone (or a condenser microphone with active circuit inside). A condenser microphone (without voltage bias source) won’t work for this circuit. If you …

Complement Phase Inverter with Single Transistor

This is a complement phase inverter circuit. Sometimes this circuit called a paraphase amplifier circuit. This circuit has two output signals that is have sufficient “headroom” because this circuit is biased. The transistor will be saturated when the collector decreases, the emitter voltage increases and set the limit. Here is the circuit: This circuit can …

Discrete (Transistors) Audio Mixer

This audio mixer is built with transistors. This audio mixer circuit is unique, not based on low input impedance amplifier. Most of audio mixer circuit is based on low impedance amplifier, so a high resistance signal source point can be summed together without disturbing each other. This mixer circuit is different, since the circuit is …

VHF-UHF Antenna Amplifier (Booster) 40-500MHz

This amplifier has VHF (very high frequency) and UHF (ultra high frequency) response, you can use it for receiver booster for example. Here is the schematic diagram of the circuit: The current consumption is very low, under 20 mA for 14V voltage supply.  Lower current consumption can be achieved if we use 10V power supply, …

Differential Amplifier with Op-Amp

The schematic diagram below shows a differential amplifier circuit. This circuit is used to get a common-mode rejection ratios. This circuit need a precise resistor matching to get common-mode rejection ratios because the current source uses matched resistor ratios. Here is the circuit: The gain of this circuit is determined by following equation: gain=R2/R1 The …

Noninverting Amplifier with Op-Amp

This is a noninverting amplifier circuit. This circuit amplify the input voltage with the same phase with output voltage. This circuit has infinite input impedance, but using 741, the input impedance would be hundreds of megaohms. The output impedance is a little, in fraction of an ohm. Here is the schematic diagram of the circuit: …