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My first public circuit here. A straightforward +48 Volt power supply for a microphone using a 555 charge pump ladder. The output at the Voltmeter should go to two perfectly matched 6.81kΩ 0.1% resistors (not shown), otherwise there could be hum from the unbalanced signal.
Semiconductors
Qty,Component,Value / Part Number,Notes
1,Timer IC,NE555 (or NE555P),Standard Bipolar version (Not CMOS).
4,Schottky Diodes,1N5819,40V, 1A. Low forward drop is key here.
1,Zener Diode,1N4756A,47V, 1 Watt. (Using 1W is safer than 0.5W for heat).
Capacitors (Electrolytic)
Qty,Value,Voltage Rating,Location
1,100 µF,25V (or higher),555 Isolation (Pin 8 to Gnd).
1,47 µF,63V,Output RC Filter (Post-Zener).
5,10 µF,63V,Charge Pump Ladder (x4) + Input Coupling (x1).
Capacitors (Ceramic / Film)
Qty,Value,Voltage Rating,Location
1,1 nF (0.001 µF),50V,555 Timing (Pin 6/2 to Gnd).
1,100 nF (0.1 µF),50V,Optional: Pin 5 (Control) to Ground. (Good practice for stability).
Resistors
Recommend 1% Metal Film, 1/4 Watt unless noted.
Qty,Value,Power Rating,Location
1,470 Ω,1/2 Watt,Current Limiting (Before Zener). dissipates heat.
2,100 Ω,1/4 Watt,(1x) Pump Driver, (1x) Output Filter.
1,22 Ω,1/4 Watt,555 Isolation (Rail to Pin 8).
1,1 kΩ,1/4 Watt,555 Timing (R1).
1,10 kΩ,1/4 Watt,555 Timing (R2).
2,6.81 kΩ,1/4 Watt,Match to 0.1%
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