Electronics and Technical resources from vu3dxr
Microphone compressor using LM1458 The LM1458 is a dual operational amplifier (op-amp) that finds applications in audio amplification and other circuits. Let’s explore how you can create a simple microphone preamplifier with compression using the LM1458. To get greater transmitting performance from your ham radio transceiver, we need to keep the modulation level constant, regardless of …
Condenser Mic audio amplifier The compact, low-cost condenser mic audio amplifier described here provides good-quality audio of 0.5 watts at 4.5 volts. It can be used as part of intercoms, walkie-talkies, low-power transmitters, and packet radio receivers. Transistors T1 and T2 form the mic preamplifier. Resistor R1 provides the necessary bias for the condenser mic …
Dual microphone noise cancellation using LF351 Op Amp Dual microphone noise cancellation (also known as Dual Mic ANC) is a technique used to improve the quality of audio captured by microphones in noisy environments. This circuit dual microphone noise cancelling using LF351 Op Amp uses two mics back to back, each amplified, one inverted, and …
Series Modulated AM Transmitter A series modulated AM Transmitter is a type of radio transmitter that uses amplitude modulation (AM) to transmit audio signals over a carrier wave. It’s known for being low-power and simple to construct, making it a good option for beginners or those interested in QRP (low-power) applications. In a series-modulated AM …
Class E – AM Transmitter A Class C AM transmitter is a type of high-efficiency, solid-state transmitter that is popular among amateur radio enthusiasts. It is known for its simplicity, affordability, and efficiency compared to other types of transmitters. Unlike Class E’s switching operation, Class C amplifiers operate in a more “on or off” manner. …
Noise Canceling Condenser Microphone Noise Canceling Electret condenser microphones are a great choice for noise-canceling applications due to their small size, low power consumption, and high sensitivity. They work in conjunction with active noise cancellation circuitry to create a more peaceful listening experience. Electret condenser microphones (ECMs) can be very effective for noise cancellation when …
Microphone compressor using two transistors Microphone compression is a useful tool that can help you to achieve a more consistent and polished sound. By reducing the gain of the loudest parts of your signal, compression can help to even out your volume levels and make your voice sound more upfront in the mix. It can …
Dynamic speech compressor or simply audio compression is an audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds, therefore reducing or compressing an audio signal’s dynamic range. Compression is commonly used in sound recording and reproduction, broadcasting, hearing aid, live sound reinforcement, and in some instrument amplifiers. There are …
One watt AM transmitter This is a simple two stage transistor ‘one watt AM transmitter’ for the HF band which gives around 1 watt in output. You can use easily available transistors like BD139, SL100, 2N3866, 2N2219 or a 2N3553 in the final stage. The output with transistor 2N3553 is approx. 1.8 watt @ 12 …
A simple series modulated AM QRP HF transmitter is a type of radio transmitter that uses amplitude modulation (AM) to transmit audio signals over a high frequency (HF) radio band. It is designed to be low-power and simple to construct, making it a good choice for beginners or those who want to build a QRP …