Precision series regulated power supply circuit diagram

The circuit principle is as shown in the figure. The center tap of the secondary N3 of the transformer T is connected to the common point of the anodes of the diodes VD2 and VD3, the cathodes of the capacitors C2, C6, C7, and the anodes of the capacitors C9 and C10 and is grounded. The ground potential is zero. The +5V regulated power supply uses an integrated block CA723 with excellent performance to automatically adjust the output voltage . Rectified by diode VD1 and filtered by capacitor C1, the positive DC voltage obtained by U1 is provided to pin 11 of CA723. Pin 6 of CA723 is a constant voltage, which is divided by resistors R4, R5 and R6, so that pin 5 can obtain the reference voltage. If the +5V output terminal voltage rises, the potential of pin 4 of CA723 rises. After comparison by the comparator in CA723, the comparison signal is sent to the error amplifier, and its pin 10 outputs a low potential to the base of the adjustment tube VT1. When the voltage between the collector and emitter of VT1 increases, the output voltage decreases and automatic voltage stabilization is achieved. If the output voltage decreases, the entire change process will change in the opposite direction.

ck="window.open(this.src)" alt="Click to see larger image" />

Main technical indicators: input voltage: 220V, 50Hz, allowable voltage change of plus or minus 10%; output DC voltage and load current: +5V 2A, +12V 1A, -12V 1A; output ripple <30mA; output voltage adjustment range: positive Minus 0.5V; this power supply has overload and short-circuit protection devices; parameters of transformer T: power: 35VA, N2: 2x12V, N3: 2x15V; ambient temperature: -10~+40 degrees Celsius.