More circuits about oscillator, pulse, frequency , and others.
If a friend gets into trouble about the noise. Try out this circuit before
The frequency meter by use the LC resonance circuit that adjustable until the frequency show peak amplitude.
This is a FM Wireless Microphone circuit Which we add one transistor in the RF amplifier. So this circuit have two resonance circuits and also two trimmers. This cause have Higher efficiency and transmission far up.
This Sawtooth wave generator circuit include of the frequency oscillator is controlled by current. Which can generate the sweep frequency in wide range. [...]
The band rejection filter circuit is not wide filter that can denial the frequency up to 60dB by we used the TL071 single chip op-amp it is very low distortion…
This am radio receiver circuit with earphone is a saving version that use a few parts, cheap , easy to build and suitable to be assembled to study,3V batt.
SEE! Simple Sine wave oscillator low frequency. Without thermistor and Incandescent lamp so very linear in transistor and zener diode circuit.