Wien bridge oscillator circuit
Basic Circuits
This wien bridge oscillator circuit which is normal,low distortion and can easily adjust the resonance frequency that depends on the pair of the resistors (R) and capacitors (C). Which we can calculate by the formula. F = 1/2 p RC In this circuit as Figure 1 the oscillator are based by the R that include with R1 + P1a (or R2 + P1b), and C is C1, C2 or either C3 (or C4, C5 or C6). And more parts are connected with IC1, IC2 op-amp ICs. Figure 1 Schematic diagram of Wien bridge oscillator circuit. The some output signal from …
6 ranges AC millivoltmeter circuits
Basic Circuits
Sometimes, we need to measure very tiny AC voltage and also high frequency. We cannot use a general meter. How it works This circuit can easily measure the very tiny AC voltage and high frequency 100 Hz to 500 Khz. Use an op-amp is the input is mosfet types, so has input impedance about 10 M ohms. The lowest full scale of this meter is 15 mV on a galvanometer 100uA. A galvanometer is a very sensitive meter to measure tiny currents, usually 1mA or less. It is analog multimeter, cheap and somewhat accurate. Best for observing the trend of …
The light meter circuit using a general diode
Meters & Detectors
This is a simple light meter circuit using normal diode as a sensor and show amount of light by a any voltmeter. The light can change the properties of many devices, example.. LDR as photo resistors can change resistance by light. Photodiode- like LDR but sensitive better than LDR, because convert light into a electricity current. Some times general photodiode may be expensive and hard to buy. When the light to a silicon diode will have very tiny current So we can easily use it instead. The 1N914 is popular number, cheapest, small and clear body. In reverse bias form, …
Precision Peak voltage detector with a long memory time.
Meters & Detectors
      If you want to check the peak voltage of the signal to change at any time. Measuring with a multimeter will not do it. We recommend this circuit. It may help you. We use this circuit The op-amp IC number CA3140 is the main equipment, acts as a voltage sensor that is accurate. So It is precision peak voltage detector circuit, and it remembers voltage value in a long memory time.       In this circuit is used with a positive signal input, when has negative feedback only. And the inverting input can only get some feedback, when diode D1-1N4148 is forward …
Nicad Charger by IC CA3140E
Battery & Charger
This is easy circuit charger batt Nicad. For batt 1.2V. When you have NiCad Battery should want to have Battery Charger Circuit. I begs for to advise NiCad Battery Charger this , because of build easy. With the integrated circuit number CA3140. Use the techinque Charger by current be stable.Make the electric charge well. But take time long little ago. however this easy good circuit sir.