How Discrete Voltage Regulator with Current Limiter Works
This discrete voltage regulator has complete features that is equivalent with modern voltage regulator integrated circuit (IC). It’s not cheaper if you build discrete one like this, but it’s always interesting to study the schematic diagram to learn how it works. Here is the schematic diagram of the circuit. Volatge Regulation Look at the 6,8k …[Read More]
230VAC Temperature Fan Control
This is a 230VAC Temperature Fan Control circuit. This circuit is used for 230Vac operation. The R9 can be changed to 15K 2W, if the AC operation is 115V. This circuit uses the principle of Wheatstone bridge. The Wheatstone bridge is made from R3-R4 and R1-P1. P1-R1 produce a temperature-sensitive “variable” voltage and a fixed …[Read More]
This transformer-rectifier-filter arrangement gives you multiple output voltages with a single transformer. This AC-DC converter can be your solution is you need two level of symmetric power supply. Here is the schematic diagram of the circuit: U1 and -U1 uses a basic symmetric supply configuration, with a center-tapped transformer and full bridge rectifier for. U2 …[Read More]
Variable Q Twin-T Notch Filter
This is a Variable Q Twin-T Notch Filter circuit. This circuit is used when low Q is needed. The Lower Q gives some advantages in rejecting the signal where the signal deviate slightly from the null of the notch network. The Q of this circuit can be adjusted from 0.3 to 50. This circuit has …[Read More]
Bootstrapped Twin-T Notch Filter Produces High Q
This is a Bootstrapped Twin-T Notch Filter circuit. This circuit can generate high Q by combining the twin “T” with LM102 voltage follower. The generated Q is greater than 50. This circuit uses small capacitors since the LM102 uses the large resistance values in the “T”. Beside that, voltage follower also used as buffer that …[Read More]
Phase-Shift Oscillator with Inverter Gates
The following circuit diagram show us another kind of CMOS oscillator. It’s will always oscillate because its a loop of three inverters. It would oscillate at a very high frequency (MHz) without the RC components depending on the propagation delays of the inverters. The RC branches give a phase shift of 60′ at some frequency, …[Read More]
Single Gate Relaxation Oscillator
Below is a relaxation oscillator circuit using a 74HC14, an inverter with a Schmitt trigger input. It’s mean that the transition point for an increasing input is higher in voltage than the transition point for a decreasing input. The difference is called the “hysteresis.” Such an input is very useful for a slowly-varying inout or …[Read More]
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