Sawtooth Generator (Oscillator) with Transistors

In the figure a, the capacitor is slowly charged through resistor R and finally after reaching the base-emitter voltage of PNP transistor, the PNP transistor begin conducting and activate the NPN transistor. The activation of NPN transistor is positively fed back to the PNP transistor so the transistors short the capacitor C to ground, discharging its voltage until zero in […]

Read more

One Transistor Pump Building Block

This is a one transistor pump circuit. This is a very simple circuit and very helpful, you can use it as a building block for designing more complex electronic circuit. This circuit generates voltage staircase from a square wave input. Here is the circuit: The V1 is determined by following equation: V1 = Vo – Vbe(sat) If the input voltage […]

Read more

Oscilloscope-Triggered Sweep using 555 IC

We can use the 555 timer to hold the cost down of adding a triggered sweep to an economy oscilloscope. The timer is triggered by the circuit’s input op amp, adjusting its flip-flop and cutting off its discharge transistor so that capacitor C can charge. The flip-flop resets and the transistor conducts when capacitor voltage reaches the timer’s control voltage […]

Read more
1 2 »
1 2