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 …[Read More]
Low Distortion Adjustable Audio frequency Oscillator
Low distortion circuit is very important if we want to measure distortion level of an audio equipment, but this is just one example of low distortion oscillator circuit application. Here is the schematic diagram: This oscillator is designed for audio application, with the adjustable frequency range of 30Hz to 20kHz, set by 470k pot. This …[Read More]
A 60Hz signal generator can be useful in testing your circuits. You can test your notch filter, simulating hum noise, or you can use it as part of your DC-to-AC inverter design. Here is the schematic diagram of the circuit: The circuit consist of twin T network built around 33k resistors and 0.068uF caps inside …[Read More]
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, …[Read More]
Multilevel Continuity Tester
This continuity tester not only show if a connection is continue or not, but also determine the range of its conductivity level. Here is the schematic diagram of the circuit: Finding wiring trouble is easier if we know the quality of the connection, and this continuity tester give rough estimation. Small transistors will be sufficient …[Read More]
Automatic AF-RF Probe
Using this automatic probe, you can see measure both audio signal (AF) and radio signal (RF). If audio signal is being measured, the path of the signal is via C1. Audio signal can’t pass the C2 since the capacitance is very small and having very high impedance for audio frequency signal. If you measure high …[Read More]
Differentiator Operator with Op-Amp
Another application of OP-AMP is differentiator. Differentiator circuit produce an output if the input is changing. The output can positive or negative, depends on the change of the input: whether it’s decreasing or increasing. This circuit is a bias stable. The current is produced by the rate of change of input voltage because the inverting …[Read More]
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